The  human  skeleton  (Lewis). 


STRUCTURE  AND  FUNCTIONS 


of 


THE  BODY 


A      HAND-BOOK     OF      ANATOMY     AND     PHYSIOLOGY     FOR 

NURSES  AND  OTHERS  DESIRING  A  PRACTICAL  KNOWLEDGE 

OF  THE  SUBJECT 


BY 


ANNETTE  FISKE,  A.  M. 

GRADUATE    OF    THE   WALTHAMXTRAINING   SCHOOL   FOR    NURSES 


ILLUSTRATED 


PHILADELPHIA  AND  LONDON 

W.  B.  SAUNDERS  COMPANY 

1911 
K  V\ 


Copyright,  191 1,  by  W.  B.  Suunders  Comixiny 


- 


PRINTED    IN    AMERICA 

PRESS    OF 

V.     8.     SAUNDER8     COMPANY 
PHILADELPHIA 


L6 

~JT4 

Mil 


TO  MY  FATHER 

and   • 
TO  DR.  ALFRED  WORCESTER 

as  those  who  have  perhaps  most  helped  me  in 

the  formation  and    realization   of   my  ideals 

this  book  is  affectionately  dedicated 


PREFACE. 


ALTHOUGH  there  are  already  in  existence  many  books 
on  anatomy  and  physiology  for  nurses,  none  with  which 
I  am  acquainted  has  seemed  to  me  to  provide  in  concise 
form  just  the  knowledge  needed  by  the  nurse  in  her 
profession.  Most  of  them,  moreover,  separate  the  anat- 
omy from  the  physiology  and  all  treat  the  different  sys- 
tems of  tissues  separately,  first  the  bones,  then  the 
muscles,  and  so  on.  These  defects,  as  they  seem  to  me, 
I  have  attempted  to  correct  not  only  by  weaving  the 
physiology  in  with  the  anatomy,  but  by  treating  first 
the  general  structures  found  throughout  the  body  and 
then  describing  the  structure  and  function  of  each  part 
in  detail.  Thus,  the  first  chapter  is  devoted  to  a  descrip- 
tion of  the  general  structure  of  all  the  tissues,  a  separate 
chapter  being  devoted,  however,  to  the  skin,  its  appen- 
dages, and  function,  including  the  sense  of  touch.  Then 
the  head  with  its  bones,  muscles,  and  organs  of  special 
sense  is  described,  while  the  brain  is  treated  with  the 
rest  of  the  nervous  system,  thus  forming  the  connecting 
link  between  the  head  and  the  body.  In  the  same  way 
the  back,  chest,  abdomen,  pelvis,  and  extremities  are 
taken  up  in  turn  and  the  bones,  muscles,  blood-vessels, 
nerves,  and  special  organs  of  each,  together  with  their 
functions,  described. 

Although  written  more  particularly  for  nurses  I  am 
in  hopes  that  this  book  may  prove  useful  to  any  others 
who  may  desire  to  acquire  a  practical  knowledge  of 
anatomy  and  physiology. 

Besides  the  usual  text-books,  I  am  much  indebted 
for  material  to  notes  taken  in  lecture  courses  given  by 

5 


6  PREFACE. 

Dr.  Fred  R.  Jouett  and  Dr.  F.  J.  Goodridge  of  Cambridge, 
Mass.,  at  the  Cambridge  School  of  Nursing,  and  by  Dr. 
Vivian  Daniel  of  Watertown  at  the  Waltham  Training 
School  for  Nurses. 

I  wish  particularly  to  express  my  gratitude  and  ap- 
preciation for  the  kind  and  helpful  criticism  given  me 
by  Dr.  Eugene  A.  Darling,  Assistant  Professor  of 
Physiology,  Harvard  College. 

ANNETTE  FISKE. 

May,  1911. 


CONTENTS. 


CHAPTER  I. 

PAGE 

COMPOSITION  AND  GENERAL  STRUCTURE  OF  THE  BODY  ...  11 
Chemical  Constitution  of  the  Body,  11— The  Cell,  12— 
The  Fundamental  Tissues  of  the  Body,  13 — Epithelial 
Tissue,  14 — Connective  Tissue,  15— Structure  of  Bone, 
17 — Bone  Formation,  18 — Chemical  Composition  of 
Bone,  18 — Classification  and  Function  of  Bones,  19 — 
Joints,  20 — Muscle,  21 — Action  of  the  Muscles,  23 — 
Physiology  of  Muscle,  24 — Cilia,  27 — The  Blood,  27— 
Arteries,  27 — Veins,  28 — Capillaries,  28 — Lymphatic 
System,  29 — Lymphatic  Vessels,  31 — Lymphatic 
Glands,  32— Lymph,  32— Glands,  35— Ductless  Glands, 
36 — Nervous  Tissue,  36. 

CHAPTER  II. 

THE  SKIN,  ITS  APPENDAGES  AND  ITS  FUNCTION 39 

The  Skin,  39 — Appendages  of  the  Skin:  Nails,  40 — Hair, 
40— Sebaceous  Glands,  41— Sweat  Glands,  42— Sweat, 
42 — Temperature  Regulation,  43 — Fever,  45 — Sense  of 
Touch,  45— Touch  Corpuscles,  46. 

CHAPTER  III. 

THE  CRANIUM  AND  FACE 48 

The  Cranial  Bones,  48— Frontal  Bone,  49— Parietal  Bones, 
49 — Occipital  Bone,  50 — Occipito-frontalis  Muscle, 
51 — Temporal  Bones,  51 — Sphenoid  or  Wedge  Bone, 
52 — Ethmoid  Bone,  53 — Turbinated  Bones,  53 — 
Ossification  of  Sutures,  53 — Bones  of  the  Face,  53 — 
Superior  Maxillary  Bones,  54 — Antrum  of  Highmore, 
54 — Malar  or  Cheek  Bones,  54 — Lachrymal  Bones,  54 — 
Palate  Bones,  54 — Nasal  Bones,  55 — Vomer,  55 — In- 
ferior Turbinated  Bones,  55 — Inferior  Maxillary  Bone 
or  Lower  Jaw,  55 — Sublingual  Gland,  56 — Submaxil- 
lary  Gland,  56. 

CHAPTER  IV. 

THE  ORGANS  OF  SPECIAL  SENSE       57 

The  Nose,  57 — The  Sense  of  Smell,  58 — The  Mouth, 
59 — The  Hyoid  Bone,  60 — The  Teeth,  60 — The  Sense 

7 


8  CONTENTS. 

PAGE 

of  Taste,  61 — Salivary  Glands,  61 — The  Tonsils,  62 — 
The  Ear,  63 — Eustachian  Tubes,  63 — Sensation  of 
Hearing,  65 — The  Eye,  66 — Lachrymal  Gland,  68 — 
Coats  of  the  Eye,  68 — Light  Rays  and  Sight,  70 — Ac- 
commodation, 72 — Color  Perception,  73. 

CHAPTER  V. 

THE  NERVOUS  SYSTEM 75 

The  Cerebrum,  75— The  Cerebellum,  78— Pons  Variolii, 
78— Medulla  Oblongata,  78— Spinal  Cord,  79— Brain- 
centers,  81 — Motor  Tract,  82 — Sensory  Tract,  82 — Re- 
flex Action,  83 — Cranial  Nerves,  83 — Spinal  Nerves,  84 
— Brachial  Plexus,  85 — Sacral  Plexus,  85 — The  Sym- 
pathetic System,  87 — The  Sympathetic  Nerves,  87. 

CHAPTER  VI. 

THE  BACK 83 

The  Spine,  88— The  Vertebrae,  88— Muscles  of  the  Neck, 
92— Muscles  of  the  Back,  93. 

CHAPTER  VII. 

THE  CHEST 98 

The  Sternum,  97 — The  Ribs,  97 — Costal  Cartilage  *, 
98 — Muscles  of  the  Chest,  98 — Diaphragm,  98 — 
Mammary  Glands,  100. 

CHAPTER  VIII. 

THE  HEART  AND  CIRCULATION 101 

The  Heart,  101 — The  Pericardium,  101 — Cavities  of  the 
Heart,  103 — The  Endocardium,  103 — The  Valves  of 
the  Heart,  103 — Circulation,  105 — Circulation  in  the 
Fetus,  106 — Arteries,  107 — Veins,  109 — Portal  Circu- 
lation, 109 — Pulmonary  Circulation,  110 — Nerves  of  the 
Heart,  110 — Heart  Sounds,  111 — The  Heart  Beat, 
111 — Factors  Affecting  Circulation,  112 — The  Pulse, 
113 — Blood  Pressure,  114 — Nerve  Supply  of  the  Blood- 
vessels, 115 — The  Blood,  116 — Composition  of  the 
Blood,  116— Coagulability  of  the  Blood,  117— Blood- 
corpuscles,  118. 

CHAPTER  IX. 

THE  LUNGS  AND  RESPIRATION      121 

The  Larynx,  121— The  Trachea,  123— The  Thyroid 
Gland,  124— The  Thymus  Gland,  124— The  Bronchi, 
125— The  Lungs,  125— The  Pleura,  125— The  Medias- 
tinum, 126 — Respiration,  127 — Air,  129 — Respiratory 
Sounds,  129 — Changes  in  Air  in  Lungs,  129 — Effect  of 
Respiration  on  Blood,  130 — Nervous  Mechanism  of 
Respiration,  130 — Variations  in  Respiration,  131. 


CONTENTS.  9 

CHAPTE] 

PAGE 

THE  ABDOMEN  AND  THE   ORGANS  OF   DIGESTION  AND  EX- 
CRETION     IV  *T^  •    • 132 

The  Abdominal  Cavity,  132 — Muscles  of  the  Abdomen, 
132 — The  Peritoneum,  134 — Abdominal  Regions,  134 
—Salivary  Digestion,  136— The  Pharynx,  136— The 
Esophagus,  138— The  Stomach,  138— Gastric  Diges- 
tion, 139 — Vomiting,  140 — Intestinal  Canal,  141 — The 
Small  Intestine,  142 — Intestinal  Digestion,  143 — Ab- 
sorption in  Intestine,  144 — The  Large  Intestine,  145 — 
Food  and  Metabolism,  147— The  Liver,  149— The  Gall- 
bladder, 152— The  Pancreas,  153— The  Spleen,  153— 
The  Suprarenal  Capsules,  154 — The  Kidneys,  155 — 
The  Urine,  156— The  Ureters,  159— The  Bladder  and 
Urethra,  159. 

CHAPTER  XI 

THE  PELVIS  AND  THE  GENITAL  ORGANS      161 

The  Pelvis,  161— The  Male  Generative  Organs,  164— The 
Prostate  Gland,  164— The  Testes,  165— The  Penis, 
165 — The  Female  Generative  Organs,  165 — The 
Ovaries,  165 — The  Fallopian  Tubes,  166 — The  Uterus, 
167 — The  Vagina,  168 — The  External  Genitalia  in  the 
Female,  169 — The  Vulva,  169 — The  Mons  Veneris, 
169 — The  Labia  Majora,  169 — The  Labia  Minora,  170 
— The  Clitoris,  170 — The  Meatus  Urinarius,  170 — 
The  Hymen,  170 — The  Fourchette,  170 — The  Perineal 
Body,  170 — The  Perineum,  170. 

CHAPTER  XII. 

THE  UPPER  EXTREMITIES      171 

The  Shoulder  Girdle,  171— The  Clavicle,  171— The 
Scapula,  173 — Shoulder  Muscles,  174 — The  Humerus, 
175— Upper  Arm  Muscles,  176— The  Ulna,  177— The 
Radius,  178— The  Wrist,  180— The  Hand,  181— Meta- 
carpals,  181 — Phalanges,  181 — Muscles  of  the  Forearm, 
182 — Muscles  of  the  Hand,  184 — Joints  of  the  Upper 
Extremity,  185 — Blood  Supply  of  the  Upper  Extrem- 
ity, 185 — Nerves  of  the  Upper  Extremity,  186. 

CHAPTER  XIII. 

THE  LOWER  EXTREMITIES 187 

The  Femur,  187 — Thigh  Muscles,  189 — The  Patella,  192 — 
Joints  of  the  Lower  Extremity,  192 — The  Tibia,  194 
—The  Fibula,  194— The  Ankle,  195— The  Foot,  195 
— Metatarsals,  195 — Phalanges,  195 — Muscles  of  the 
Leg,  196 — The  Blood  Supply  of  the  Lower  Extremity, 
198 — Nerves  of  the  Lower  Extremity,  199. 

INDEX   .  .    201 


STRUCTURE  AND 
FUNCTIONS  OF  THE  BODY. 


CHAPTER  I. 

COMPOSITION  AND  GENERAL  STRUCTURE  OF  THE 

BODY. 

Anatomy  is  the  study  of  the  physical  structure  and 
physiology  the  study  of  the  normal  functions  of  the 
human  body. 

Chemical  Constitution  of  the  Body. — In  the  body  only 
twenty  elements  have  been  found.  These  include  car- 
bon, oxygen,  hydrogen,  nitrogen,  sulphur,  phosphorus, 
calcium,  magnesium,  manganese,  chlorin,  potassium,  and 
fluorin.  For  the  most  part  they  appear  in  very  complex 
and  highly  unstable  combinations,  though  oxygen  and 
nitrogen  may  be  said  to  exist  uncombined  in  the  blood, 
alimentary  canal,  and  lungs.  Hydrogen  also  occurs  in 
simple  form  in  the  alimentary  canal,  but  as  the  result 
of  fermentation,  not  as  an  element  of  the  body. 

Of  the  organic  compounds  some  contain  nitrogen  and 
some  do  not.  The  most  important  of  the  former  are  the 
proteins,  which  are  found  only  in  living  bodies  and  consist 
of  carbon,  hydrogen,  oxygen,  nitrogen,  and  sulphur 
combined  in  very  similar  proportions.  The  important 
proteins  in  the  body  are  the  serum  albumen  and  fibrin 
found  in  the  blood,  myosin  in  muscle,  globulin  in  the 
red  blood-corpuscles,  and  casein  in  the  milk.  Similar  to 
the  proteins  but  capable  of  passing  through  membranes 

11 


12  GENERAL    STRUCTURE    OF   THE    BODY. 

are  the  peptones,  the  final  result  of  protein  digestion, 
from  which  the  albuminoids  differ  in  that  they  contain 
no  sulphur.  Ferments  containing  nitrogen  exist  in  all 
the  cells  of  the  body,  though  more  particularly  in  those  of 
the  digestive  organs,  and  the  coloring  matters,  as  the 
bilirubin  of  the  bile,  are  nitrogenous. 

The  organic  substances  that  do  not  contain  nitrogen 
are  the  carbohydrates  or  starches,  the  hydrocarbons  or 
fats,  and  the  acids,  of  which  the  most  important  is  cnr- 
bon  dioxide,  given  off  by  the  lungs. 

The  inorganic  substances  are  water,  which  forms  a 
large  percentage  of  all  the  tissues  and  from  one-fourth 
to  one-third  of  the  whole  body  weight,  sodium  chloride 
or  common  salt,  which  plays  an  important  part  in  keep- 
ing substances  in  solution,  potassium  and  magnesium 
chloride,  and  hydrochloric  acid,  found  in  the  stomach. 

The  Cell. — Although  the  body  is  a  very  complex  organ- 
ism, the  cell  is  its  unit  or  foundation.  In  fact,  the  body 
begins  life  as  a  single  protoplasmic  cell,  the  ovum,  which 
is  frequently  compared  to  the  amoeba,  a  microscopic 
animal  consisting  of  a  single  cell  of  protoplasm  or  living 
substance — a  substance  not  well  understood  as  yet — but 
possessing  practically  all  the  functions  of  the  human  body. 
For,  although  it  has  no  organs  and  is  homogeneous  in 
structure,  the  amoeba  can  move  by  throwing  out  a  pro- 
cess, and  can  surround  and  absorb  food,  which  it  builds 
up  into  new  tissue,  discarding  the  waste.  The  ovum, 
however,  differs'  from  the  amceba  in  that  it  has  a  trans- 
parent limiting  membrane  and  contains  a  darker  spot, 
the  nucleus.  This  in  turn  contains  another  smaller  spot, 
the  nucleolus,  while  through  the  protoplasm,  which  is 
semi-fluid,  extends  a  fine  network  that  seems  to  hold  it 
in  place. 

The  ovum  is  very  small,  about  y^-y  inch  in  diameter, 
and  after  fertilization  grows  by  segmentation,  the  nucleus 
dividing  in  two  and  the  protoplasm  grouping  itself  anc\v 
about  the  two  nuclei.  This  division  continues,  each  cell 
dividing  and  forming  two,  or  sometimes  four,  new  cells, 


GENERAL    STRUCTURE    OF    THE    BODY.  13 

all  of  which  at  first  appear  alike.  By  degrees,  however, 
differentiation  takes  place  and  different  groups  of  cells 
assume  different  characteristics.  Thus  the  various 
tissues  are  gradually  developed,  each  with  a  structure 
and  a  function  of  its  own,  and  are  distributed  among  the 
various  organs,  each  organ  consisting  of  several  tissues. 
During  the  process  of  growth  and  even  after  full  growth 
of  the  body  is  attained  old  cells  are  continually  dying  and 
being  replaced  by  new  ones. 

The  typical  cell  is  circular,  but  through  being  squeezed 
together  in  the  tissues  or  for  some  other  reason  the  cells 
vary  in  shape  in  different  parts,  being  at  times  hexagonal, 
spindle-shaped,  or  columnar.  Yet,  whatever  their  differ- 
ences in  shape  or  other  characteristics,  they  all  live  the 
same  sort  of  life.  All  protoplasm  absorbs  oxygen  when 
it  comes  in  contact  with  it  and  in  the  process  of  combin- 
ing with  it  is  in  part  burned  or  oxidized,  with  the  conse- 
quent setting  free  of  heat  and  other  forms  of  energy  and 
the  formation  of  carbon  dioxide.  So  long  as  the  body 
is  alive,  therefore,  whether  it -is  in  a  state  of  activity  or  of 
rest,  it  is  the  seat  of  constant  chemical  change  through- 
out all  its  cells,  and  to  these  chemical  changes  are  due  all 
the  forms  of  energy  manifested  by  the  body.  For  energy 
is  never  destroyed,  though  it  may  appear  in  a  different 
form,  and  the  elements  of  the  human  body  are  so  com- 
bined that  their  energy  may  be  liberated  and  manifested 
in  the  different  functions  the  body  exhibits. 

The  fundamental  tissues  of  the  body  are  the  epithelial 
tissues,  the  connective  tissues,  including  the  cartilagin- 
ous and  bony  tissues,  and  the  muscular  and  nervous 
tissues.  Of  these  the  epithelial  tissues  serve  as  a  protec- 
tion to  the  surface  of  other  tissues;  the  connective  tissues 
together  form  a  framework  for  the  support  and  general 
protection  of  the  other  tissues;  while  energy  is  expended 
by  muscular  and  nervous  tissue,  the  latter  directing  the 
former  in  its  movements.  All  the  tissues  are  inter- 
dependent and  the  organs  work  together.  Besides  cells 
every  tissue  contains  a  certain  amount  of  lifeless  matter, 


14  GENERAL    STRUCTURE    OF    THE    BODY. 

the  intercellular  substance,  which  was  at  some  time  pro- 
duced by  the  cells. 

In  epithelial  tissue  there  is  little  intercellular  substance, 
the  cells  being  close  together  and  arranged  generally  as  a 
skin  or  membrane  covering  external  or  internal  surfaces. 
When  there  are  several  layers  of  cells,  the  deepest  are 
columnar  in  shape  and  the  others  become  more  and  more 
flattened  and  scale-like  as  they  approach  the  surface, 
where  they  are  gradually  rubbed  off  and  replaced  by  the 
growth  of  new  cells  from  below.  This  stratified  epithe- 
lium, as  it  is  called,  is  found  wherever  a  surface  is  exposed 


FIG.  1. — Epithelium:    1,  pavement   epithelium;     2,  columnar   epithelium;     3, 
ciliated  epithelium;  4,  stratified  epithelium. 

to  friction,  as  in  the  skin  and  in  the  mucous  membrane  of 
the  mouth,  pharynx,  and  esophagus,  and  in  that  of  the 
vagina  and  the  neck  of  the  uterus.  In  simple  epithelium, 
where  there  is  only  a  single  layer  of  cells,  the  cells  may  be 
pavement  or  hexagonal,  columnar,  glandular,  or  ciliated, 
according  to  their  different  functions.  The  flat  pave- 
ment cells  occur  where  a  very  smooth  surface  is  required, 
as  in  the  heart,  lungs,  blood-vessels,  serous  cavities,  etc. 
None  of  these  surfaces  communicate  directly  with  the 
external  surface  of  the  body  and  the  name  endothelium  is 
substituted  for  epithelium.  The  columnar  form  of  cell  in 
the  intestine  facilitates  the  passage  of  leucocytes  between 
the  cells.  In  glandular  epithelium  the  cells  vary  accord- 
ing to  the  gland  in  which  they  occur,  their  protoplasm 


^.  HOSp/7> 

GENERAL    STRUCTURE    Qt\JHE    BODY.  15 

TRAINING  SCHC 

being  filled  with  the  material  the  gland  secretes.  Finally, 
ciliated  epithelium  is  composed  cH^columnar  cells  with 
cilia  or  little  hair-like  processes  upo 
which  serve  to  send  secreted  fluids  and  other  matters 
along  the  surfaces  where  they  occur,  as  in  the  air  pas- 
sages, parts  of  the  generative  organs,  the  ventricles  of 
the  brain,  and  the  central  canal  of  the  spinal  cord. 

Connective  tissue  has  a  great  deal  of  intercellular  sub- 
stance. One  form,  areolar  tissue,  is  composed  of  a  loose 
network  of  fine  white  fibers  with  a  few  yellow  elastic 
fibers  interspersed  and  with  cells  lying  in  the  spaces 


Pavement  cell. 
Pear-shaped  cell. 

Interstitial  cell. 


FIG.  2. — Section  of  bladder  epithelium.    (Hill.) 

between  the  fibers.  It  connects  and  surrounds  the  differ- 
ent organs  and  parts,  holding  them  together,  yet  allowing 
free  motion,  and  is  one  of  the  most  extensively  distrib- 
uted of  the  tissues.  It  is  continuous  throughout. 

Closely  allied  to  the  areolar  is  the  fibrous  tissue,  in 
which  the  white  fibers  lie  close  together  and  run  for  the 
most  part  in  one  direction  only.  This  is  found  in  liga- 
ments, joints  and  tendons,  as  also  in  such  fibrous  pro- 
tective membranes  as  the  periosteum,  dura  mater,  the 
fascia  of  muscles,  etc.  Fibrous  tissue  is  silvery  white  in 
appearance  and  is  very  strong  and  tough,  yet  pliant. 
It  is  not  extensile. 

Elastic  tissue,  on  the  other  hand,  has  a  large  predomi- 
nance of  yellow  elastic  fibers  and  is  very  extensile  and 
elastic,  though  not  so  strong  as  the  fibrous.  It  is  found 
in  the  walls  of  the  blood-vessels,  especially  the  arteries, 


16  (iKXKKAl.   8TBUCTURE    OF   THE    BODY. 

in   the   walls   of   the   air   tubes,   in   (lie   ligaments   of   the 
spine,  etc. 

Fiiltij  or  W///JO.XT  ttNtiuc  is  formed  by  the  deposit  of  fat 
in  the  cells  of  the  areolar  tissue  and  is  found  in  most 
pails  where  the  areolar  tissue  occurs,  though  it  varies 
largely  in  amount  in  different  parts.  It  is  found  pretty 
generally  under  the  skin,  fills  in  inequalities  about  vari- 
ous organs  and  about  the  joints,  and  exists  in  large  quan- 


*, 


2* 

d-^          :-i^V-'^.  '  -' 

~ 

FIG.  3. — Adipose  tissue  (Leroy):  a.  Fibrous  tissue;  6,  fat  cells;  c,    nucleus   of 
fat  cells;  d,  fatty  acid  crystals  in  fat  cells. 

titles  in  the  marrow  of  the  long  bones.  In  moderate 
amounts  it  gives  grace  to  the  form  and  constitutes  an 
important  reserve  fund. 

Cartilage  consists  of  groups  of  nucleated  cells  in  inter- 
cellular substance.  It  is  very  firm,  yet  highly  elastic,  and 
serves  in  the  joints  to  break  the  force  of  concussion  of  the 
harder  and  less  elastic  bones.  Except  when  it  occurs  at 
the  end  of  a  bone,  it  is  covered  with  a  membrane  called 
the  perichondrium,  which  carries  its  blood  supply.  In 
the  nose,  ear,  larynx  and  trachea  it  serves  to  give  shape, 
to  keep  the  passages  open,  and  to  afford  attachment  for 


GENERAL   STRUCTURE    OF   THE    BODY. 


17 


muscles.  Most  of  the  skeleton  of  the  fetus  consists  of 
cartilage,  which  later  develops  into  bone. 

Bone. — In  bone  the  intercellular  tissue  is  rendered 
hard  by  the  deposit  of  mineral  salts,  the  resulting  material 
being  of  great  strength  and  rigidity.  The  texture  may 
be  close  and  dense  like  ivory  or  open  and  spongy,  the 
difference  lying  merely  in  the  fact  that  the  one  has  fewer 
spaces  between  the  solid  particles  than  the  other.  There 
is  usually  a  hard,  compact  layer  on  the  exterior  of  the 
bone,  as  that  is  where  the  greatest  cross-strain  comes, 
especially  in  the  long  bones,  while  within  is  the  cancellous 
or  spongy  tissue,  which  gives  lightness  to  the  bone  and 
is  capable  of  withstanding  enormous  pressure,  though 
it  can  bear  little  cross-strain. 

Structure  of  Bone. — The  hard  substance  in  bone  is 
always  arranged  in  lamellae  or  bundles  of  bony  fibers, 


Haversian  canal. 


Lacuna  and  canaliculi. 


FIG.  4. — Cross-section  of  compact  bone  tissue.     (After  Sharpey.) 

which  in  cancellous  tissue  meet  to  form  a  kind  of  lattice- 
work, while  in  the  dense  tissue  they  are  generally  ar- 
ranged in  rings  about  the  Haversian  canals,  channels 
through  which  the  blood-vessels  pass  through  the  bone 
longitudinally.  Between  the  lamellae  are  spaces  called 
lacunce,  in  which  lie  branched  cells,  the  spaces  being 
connected  with  each  other  and  with  the  Haversian 
canals  by  numerous  tiny  canals  or  canaliculi,  by  which 
2 


18  GENERAL   STRUCTURE    OF   THE    BODY. 

nutrient  material  finds  its  way  from  the  Haversian  canals 
to  all  parts  of  the  bone. 

Within  the  bone  is  the  medulla  or  marrow,  which  is  of 
two  varieties:  the  yellow,  which  is  largely  fat  and  is  found 
in  the  long  bones  of  adults,  and  the  red,  which  is  nearly 
three-fourths  water  and  is  found  in  most  of  the  other 
adult  bones  and  in  the  bones  of  the  fetus  and  of  the 
infant. 

Lining  the  medullary  and  cancellous  cavities  is  a 
delicate  connective  tissue  lining,  the  endosteum,  which 
contains  many  bone-forming  cells,  while  on  the  outside 
of  the  bone,  except  at  the  articular  ends,  is  the  perios- 
teum with  its  outer  protective  layer  and  its  inner  vas- 
cular layer  containing  osteoblasts  or  bone-forming  cells. 
The  periosteum  is  essential  for  the  growth  of  new  bone 
where  the  old  bone  has  died,  and  if  the  periosteum  is 
removed  from  healthy  bone  the  part  beneath  is  liable  to 
die,  as  it  is  by  the  constant  growth  of  the  osteoblasts 
that  the  bone  grows  and  is  renewed.  In  the  repair  of 
broken  bones  tissue  is  formed  between  and  around  the 
broken  ends. 

Bone  Formation. — Most  of  the  skull  and  face  bones 
begin  as  membranes  of  connective  tissue,  that  is,  are 
formed  in  membrane.  Bones  are  also  formed  in  carti- 
lage, the  bone  formation  in  this  case  beginning  from 
centers  of  ossification,  where  the  deposit  of  lime  salts  in 
the  intercellular  substance  begins,  the  salts  coming  to 
the  centers  dissolved  in  the  plasma.  Such  a  center  of 
growth  in  a  bone  is  called  the  epiphysis  and  is  separated 
from  the  main  part  of  the  bone  or  diaphysis  by  cartilage 
until  full  growth  is  attained,  when  ossification  becomes 
complete.  So  in  surgery,  in  working  on  the  bones  of 
children,  part  of  the  epiphysis  should  always  be  left  for 
the  sake  of  future  growth.  The  outer  shell  of  compact 
tissue  is  deposited  by  the  periosteum. 

Chemical  Composition  of  Bone. — Chemically  bone  is 
composed  of  about  one-third  organic  or  animal  matter, 
largely  gelatine,  and  two-thirds  inorganic  matter,  includ- 


GENERAL    STRUCTURE    OF    THE    BODY.  19 

ing  various  salts  of  calcium,  magnesium,  and  sodium. 
In  young  children  the  animal  matter  predominates  and 
the  bones  are  soft  and  often  bend  instead  of  breaking, 
only  the  outside  shell  on  one  side  giving  way,  as  in  "  green- 
stick"  fracture.  In  rickets  there  is  a  deficiency  of  lime 
salts,  but  the  increased  brittleness  of  the  bones  in  old 
age  is  due,  not  to  increase  of  mineral  matter,  but  to  the 
less  spongy  texture  of  old  bones. 

Classification  and  Function  of  Bones. — There  are  in  the 
body  some  two  hundred  bones,  which  may  be  classified 
as  long,  short,  flat,  and  irregular.  Occasionally  an  ir- 
regular bone  develops  in  a  fontanelle,  the  membranous 
opening  at  the  juncture  of  the  sutures  of  the  skull. 
This  is  known  as  a  Wormian  bone.  It  is  not,  however, 
included  in  the  two  hundred,  as  are  not  the  sesamoid 
bones  or  bones  developed  in  tendons,  with  the  exception 
of  the  patella  or  knee-cap. 

Long  bones  are  developed  in  cartilage  and  consist  of  a 
shaft,  two  extremities,  and  various  processes.  They  are 
more  or  less  curved  to  give  them  strength  and  grace. 
They  serve  as  supports  and  act  as  levers  for  purposes  of 
motion  and  the  exercise  of  power.  Since  a  hollow  cyl- 
inder is  just  as  strong  as  a  solid  one  of  the  same  size,  the 
weight  coming  only  on  the  outer  shell,  the  great  bones 
which  are  accountable  for  weight  and  which  need  to  be 
light  themselves  have  hollow  shafts,  composed  chiefly  of 
compact  tissue  with  a  central  medullary  canal.  The 
ends,  however,  are  expanded  in  order  to  make  better 
connection  at  the  joints  and  to  afford  broad  surfaces 
for  muscular  attachment-,  cancellous  tissue  being  used 
in  them  for  lightness  and  strength.  The  large  spongy 
ends  also  give  elasticity  and  lessen  jar,  and  by  bringing 
the  tendons  to  the  bone  at  a  greater  angle  increase  their 
effectiveness.  Blood  is  brought  to  the  long  bones  not 
only  by  the  vessels  of  the  periosteum  but  by  the  medul- 
lary artery,  which  penetrates  the  compact  tissue  by  the 
nutrient  foramen  and  divides  into  an  ascending  and  a 
descending  branch. 


20  GENERAL   STRUCTURE    OF    THE    BODY. 

Short  bones  are  spongy  throughout.  They  are  used 
for  strength  and  where  little  motion  is  required. 

Flat  bones  are  composed  of  two  thin  layers  of  compact 
tissue  with  a  varying  amount  of  cancellous  tissue  be- 
tween, and  are  for  protection  and  muscular  attachment. 
The  cancellous  material  between  the  two  layers  or  tablets 
of  the  skull  is  called  the  diploe. 

Eminences  and  depressions  occur  on  bones  and  when 
they  are  not  articular  are  for  the  attachment  of  ligaments 
and  muscles.  If  they  are  articular,  they  help  to  form 
joints. 

As  a  whole  the  bony  framework  serves  to  keep  the 
soft  parts  in  place,  to  support  and  protect  them,  and  to 
aid  in  locomotion.  The  bones  of  the  head  and  trunk 
support  and  protect  organs;  those  of  the  arms  are  for 
tact  and  prehension;  those  of  the  lower  extremities  are 
for  support  and  locomotion. 

Normally  bones  have  little  sensibility,  but  when  in- 
flamed they  are  extremely  sensitive  and  painful. 

Joints. — The  bones  are  connected  with  and  move  upon 
one  another  by  means  of  joints.  These  joints  are  of 
three  kinds:  1.  Immovable,  where  the  adjacent  margins 
of  the  bones  are  closely  applied,  with  little  fibrous  tissue 
between,  as  in  the  sutures  of  the  head;  2.  those  with 
limited  motion,  which  are  very  strong,  the  parts  being 
connected  with  tough  fibre-cartilage;  and  3.  freely  mov- 
able. In  this  last  group  the  articulating  surfaces  are 
covered  with  cartilage,  which  again  is  lined  with  a  deli- 
cate synovial  membrane  which  secretes  a  small  amount 
of  lubricating  fluid,  the  synovial  fluid,  to  reduce  friction. 
Their  surfaces  are  also  sometimes  deepened  by  the  pres- 
ence of  interarticular  fibro-cartilages.  Bursse  or  sacs  of 
synovial  membrane  occur  outside  the  joints  under  ten- 
dons and  ligaments  to  reduce  friction. 

The  nature  and  extent  of  the  motion  of  a  joint  is 
defined  and  the  bones  are  held  together  by  strong  bands 
of  fibrous  tissue  or  ligaments,  these  ligaments  being  more 
fully  developed  in  joints  where  there  is  great  freedom  of 


GENERAL    STRUCTURE    OF    THE    BODY.  21 

motion  or  where  there  is  great  weight  to  be  supported. 
In  a  ball-and-socket  joint,  such  as  the  hip,  there  is  a 
ligament  in  the  form  of  a  strong  capsule  which  surrounds 
the  joint  on  all  sides  and  limits  its  motion,  while  hinge 
joints,  like  the  elbow,  and  pivot  joints,  such  as  that 
formed  by  the  atlas  on  the  axis,  have  lateral  ligaments 
that  allow  of  freer  motion.  In  the  shoulder-joint,  which 
is  the  most  freely  movable  joint  in  the  body,  the  capsular 
ligament  is  very  lax. 

In  general  the  kinds  of  motion  possible  in  joints  may 
be  said  to  be  flexion,  extension,  abduction,  adduction, 
circumduction,  and  rotation. 

When  much  violence  is  applied  to  a  joint  and  no  dis- 
location results,  as  in  a  sprain,  there  is  often  much 
stretching  and  even  laceration  of  the  ligaments. 

Muscle. — The  flesh,  which  forms  a  large  proportion  of 
the  weight  of  the  body,  consists  of  muscular  tissue.  Of 
this  two  kinds  are  found:  1.  The  striated  or  striped 
muscle  of  animal  life,  which  is  under  the  control  of  the  will 
and  so  is  known  as  voluntary  muscle,  and  2.  the  unstriped 
or  smooth  muscle  of  organic  life  over  which  we  have  no 
control,  that  is,  the  involuntary  muscle.  Each  fiber  of 
striped  muscle  has  an  elastic,  membranous  sheath,  the 
sarcolemma,  and  consists  of  rod-shaped  cells  with  a 
nucleus  along  the  edge,  set  end  to  end  and  having  cross- 
wise striations.  In  unstriated  muscle  the  fibers,  which 
have  no  sarcolemma,  consist  of  oval  or  spindle-shaped 
cells,  with  a  nucleus  much  smaller  than  that  of  striped 
muscle  and  situated  in  the  middle.  In  both  kinds  of 
muscle  the  fibers  are  bound  together  with  connective 
tissue  and  blood-vessels  into  fasciculi  or  bundles,  and 
many  bundles  go  to  make  up  a  muscle.  The  muscle  in 
turn  has  a  connective  tissue  envelope  or  sheath,  the 
fascia.  These  fasciae  are  found  throughout  the  body,  the 
superficial  ones  being  just  beneath  the  skin,  while  the 
deep  ones  not  only  form  sheaths  for  the  various  mus- 
cles but  form  partitions  between  them  and  serve  to 
strengthen  their  attachments.  The  striped  muscles  are 


22 


GENERAL   STRUCTURE   OF   THE    BODY. 


those  of  motion,  while  the  unstriped  occur  in  the  hollow 
organs,  surrounding  the  cavity  and  in  some  cases  lessen- 
ing its  capacity  by  their  contraction. 

An  intermediate  form  of  muscle  known  as  cardiac 
muscle  occurs  in  the  heart.  Here  the  fibers  have  stria- 
tions  but  the  nucleus  is  generally  in  the  middle  of  the 
cell  and  the  fibers  branch  and  run  together. 


FIG.  5. — Voluntary  muscle  (Leroy).  A,  Three  voluntary  fibers  in  long  sec- 
tions: a,  three  voluntary  muscle  fibers;  6,  nuclei  of  same  ;c,  fibrous  tissue  between 
the  fibers  (endomysium) ;  d,  fibers  separated  into  sarcostyles.  B,  Fiber  (diagram- 
matic): a,  dark  band;  b,  light  band;  c,  median  line  of  Hensen;  d,  membrane  of 
Krause;  e,  sarcolemma;  /,  nucleus.  C:  a,  Light  band;  b,  dark  band;  c,  contract- 
ing elements;  d,  row  of  dots  composing  the  membrane  of  Krause;  e,  slight 
narrowing  of  contracting  element  aiding  in  production  of  median  line  of  Hensen. 

In  life  muscle  appears  more  or  less  translucent  and 
is  contractile  and  alkaline,  but  in  death  it  loses  its  trans- 
lucency  and  becomes  rigid,  at  the  same  time  giving  off 
in  decomposition  much  carbon  dioxide,  so  that  its  re- 
action is  acid.  This  phenomenon  of  the  muscles  be- 
coming rigid  in  death  is  called  rigor  mortis  and  occurs 
generally  a  few  hours  after  death,  though  it  may  come 


GENERAL   STRUCTURE    OF   THE    BODY.  23 

at  once  or  be  considerably  delayed.  It  may  last  any- 
where from  a  few  moments  to  several  days  but  gener- 
ally lasts  from  twenty-four  to  thirty-six  hours.  It  is 
probably  due  to  the  formation  in  the  muscle  of  myosin, 
a  substance  which  probably  comes  from  myosinogen 
in  the  living  muscle  and  which  is  closely  akin  to  the 
fibrin  of  blood.  Probably  the  myosin  or  what  precedes 
it  causes  clotting  of  the  muscle  just  as  fibrin  or  what 
precedes  it  causes  clotting  of  the  blood. 

The  muscles  vary  in  shape  in  different  parts  of  the 
body,  being  long  and  slender  in  the  limbs  and  broad  and 
flat  in  the  trunk.  They  are  attached  chiefly  to  bones 


FIG.  6. — Three   voluntary    muscle    fibers    from    an    injected  muscle,  showing 
network  of  blood  capillaries.     (Hill.) 

but  also  to  cartilages,  ligaments,  and  skin,  either  by 
means  of  tendons,  which  are  cords  or  bands  of  white 
inelastic  fibrous  tissue,  or  by  means  of  aponeuroses, 
membranous  expansions  of  the  same  nature.  Most 
voluntary  muscles  consist  of  a  belly  and  two  ends  or 
tendons.  The  origin  is  the  fixed  point  from  which  it 
acts  while  the  movable^  point  upon  which  it  acts  is 
known  as  its  insertion. 

Action  of  the  Muscles. — When  attached  to  bones,  mus- 
cles are  distributed  in  three  ways:  1.  When  it  is  neces- 
sary to  produce  much  motion  rapidly,  a  short  muscle  is 
used.  2.  When  a  part  needs  to  be  moved  far  and 
much  contraction  on  the  part  of  the  muscle  is,  there- 
fore, needed,  the  muscle  is  very  long,  as  in  the  case  of 
the  sartorius  muscle,  which  shortens  half  its  length.  3, 


24  GENERAL   STRUCTURE    OF   THE    BODY. 

Finally,  where  less  distance  has  to  be  covered  but 
greater  power  is  required,  tendons  are  used,  as  in  this 
case  the  contraction  is  powerful  but  does  not  carry 
the  part  far. 

In  performing  the  mechanical  work  of  the  body  the 
muscles  are  aided  by  the  fact  that  the  bones,  to  which 
they  are  largely  attached,  are  set  together  loosely  and 
form  a  set  of  levers,  on  which  the  muscles  act  to  perform 
certain  definite  acts.  All  three  classes  of  levers  occur: 
1.  where  the  fulcrum  is  between  the  weight  and  the 
power,  as  in  the  case  of  the  head,  which  is  balanced  by 
the  muscles  of  the  neck  on  the  vertebrae;  2.  where 
the  weight  is  between  the  fulcrum  and  the  power,  as 
when  a  person  raises  himself  upon  his  toes;  and  3. 
where  the  power  is  between  the  fulcrum  and  the  weight, 
as  when  the  biceps  is  used  to  raise  a  weight  held  in  the 
hand.  The  erect  position  of  the  body  is  difficult  to 
maintain  because  the  center  of  gravity  is  high  up,  and  it  is 
by  the  contraction  of  many  muscles  in  the  legs,  thighs, 
back,  abdomen,  and  neck  that  the  body  is  balanced 
upright  upon  the  feet. 

Physiology  of  Muscle. — Irritability  or  sensitiveness  to 
stimulation  and  contractility  or  the  power  to  contract 
are  the  two  most  important  functions  of  muscle.  Con- 
traction occurs  in  response  to  nervous  energy  brought 
by  the  nerves,  a  nerve  filament  going  to  each  muscle 
fiber,  into  which  it  plunges,  its  substance  being  lost  and 
its  sheath  becoming  continuous  with  that  of  the  mus- 
cle fiber.  Any  irritant,  as  heat,  electricity,  etc.,  when 
applied  to  the  nerve,  causes  the  muscle  to  contract. 
Moreover,  muscle  has  an  irritability  of  its  own  and 
can  contract  independently  of  the  nervous  system.  In 
contracting  it  shortens  and  thickens,  bringing  the  two 
ends  closer  together,  and  becomes  firm  and  rigid.  The 
amount  of  contraction  depends  upon  the  strength  of  the 
stimulus  and  the  irritability  of  the  muscle.  The  mini- 
mal stimulus  is  the  least  stimulus  that  will  cause  a  con- 
traction and  the  maximal  is  one  that  will  cause  the  great- 


GENERAL    STRUCTURE    OF    THE    BODY.  25 

est  contraction.  The  work  done  depends  in  like  manner 
upon  the  strength  of  the  stimulus.  During  contraction 
certain  sounds  are  given  off  called  muscle  sounds,  which 
can  be  heard  with  the  stethoscope  but  have  no  special 
significance. 

The  muscles  which  have  the  greatest  power  of  rapid 
contraction  are  generally  attached  to  levers.  Indeed, 
striated  muscle  is  characterized  by  the  rapidity  and 
strength  with  which  it  works,  though  its  rhythmic  mo- 
tion is  slight.  Smooth  muscle,  on  the  other  hand,  is 
characterized  by  its  great  force,  considerable  rhythm, 
considerable  tone,  and  slight  rapidity,  that  is,  its  con- 
traction is  slower  and  lasts  longer  than  that  of  striated 
muscle.  Cardiac  muscle  is  characterized  by  great  rhythm 
and  force,  fair  rapidity,  and  slight  tonicity,  tonicity 
being  the  amount  of  tone  or  readiness  to  work.  For 
even  in  sleep  muscle  is  always  in  tone,  that  is,  ready  to 
do  its  work.  It  is  this  that  makes  the  difference  in  ap- 
pearance between  a  living  and  a  dead  person  and  en- 
ables one  to  spring  to  his  feet  at  night  if  he  hears  a  noise, 
a  thing  he  could  not  do  if  his  muscles  were  wholly  re- 
laxed. Thus,  rapidity  is  the  great  function  of  striated, 
tonicity  of  smooth,  and  rhythm  of  cardiac  muscle.  In 
paralysis  the  muscles  droop  and  lose  their  tone.  Mus- 
cles are  frequently  the  seat  of  rheumatic  disorders. 

When  set  free,  potential  energy  accomplishes  work. 
In  muscle  there  is  a  good  deal  of  potential  energy, 
which  is  set  free  as  heat  and  as  work  accomplished. 
Even  when  the  muscles  are  at  rest,  chemical  changes  are 
going  on  and  heat  is  being  produced,  though  more  heat 
is  produced  when  they  are  functioning.  If  the  body  de- 
pended upon  its  gross  motions  for  all  its  heat  it  would 
grow  cold  while  a  person  rested.  The  respiratory  or- 
gans, however,  and  the  heart  are  always  working  and 
chemical  changes  are  constantly  taking  place. 

Ordinarily  a  muscle  has  some  object  in  contracting, 
such  as  the  raising  of  a  load,  and  it  contracts  voluntarily 
more  or  less  according  to  the  weight  of  the  load.  The 


26  GENERAL   STRUCTURE    OF   THE    BODY. 

amount  of  work  done  is  calculated  in  foot-pounds  or 
gram-meters,  that  is,  the  energy  required  to  raise  one 
pound  one  foot  or  one  gram  one  meter.  As  a  rule  the 
muscles  with  the  longest  fibers,  as  the  biceps,  do  the 
most  work  and  those  with  a  large  number  of  fibers  do 
more  than  those  with  less.  It  has  been  calculated  that 
whereas  an  engine  gives  back  one-twelfth  of  the  energy 
of  the  coal  consumed,  muscle  liberates  one-fourth  of  the 
energy  brought  to  it  in  the  form  of  food.  During  ac- 
tivity the  glycogen  or  sugar  in  the  muscle  is  used  up  and 
the  muscle  becomes  more  acid,  owing  to  the  lactic  acid 
that  is  formed.  The  carbon  is  taken  in  and  carbon  di- 
oxide given  off.  Nitrogen  puts  the  muscle  in  condition 
to  do  its  work  but  is  not  so  much  used  up  in  the  work  as 
is  the  carbohydrate  material.  So  it  is  the  non-nitrogen- 
ous matter  that  does  the  work  and  any  increase  in  urea, 
the  end-product  of  protein  metabolism,  is  mere  wear  and 
tear. 

Sudden  heat  or  cold  causes  muscular  contraction  and 
moderate  heat  favors  both  muscular  and  nervous  irri- 
tability. Moderate  cold,  however,  lessens  the  force  of 
contraction  and  below  zero  muscle  very  largely  loses 
its  irritability  without  necessarily  becoming  rigid. 

While  well  supplied  with  blood,  muscle  will  contract 
without  fatigue,  but  if  the  blood  supply  is  shut  off,  it 
soon  loses  its  irritability  and  becomes  rigid.  The  more 
a  muscle  is  used  in  moderation  the  more  it  develops,  but 
after  it  has  done  a  certain  amount  of  work  it  becomes 
exhausted,  losing  its  irritability  or  power  to  respond  to 
stimuli  and  later  becoming  rigid.  Such  fatigue  is  due 
to  the  production  of  certain  poisonous  waste  products 
which  have  a  paralyzing  effect  on  the  nerves  and  which 
are  ordinarily  gradually  carried  away  in  the  blood,  but 
which  sometimes,  if  produced  to  excess,  accumulate 
too  fast  for  the  blood  wholly  to  remove  them.  Usually 
the  nerve  becomes  exhausted  first  and  the  muscle  sub- 
stance later.  So  long  as  it  is  connected  with  the  nervous 
system  a  muscle  will  respond  to  stimuli,  but  when  the 


GENERAL    STRUCTURE    OF   THE    BODY.  27 

nerve  becomes  tired,  degeneration  is  more  rapid.  In 
fact,  the  degree  of  exhaustion  is  determined  by  several 
factors,  as  by  relation  to  the  central  nervous  system, 
variations  in  temperature,  blood  supply,  and  functional 
activity,  the  process  being  more  rapid  in  warm  than  in 
cold  blooded  animals. 

Cilia. — A  few  motions  are  accomplished  by  tissue  that 
is  not  muscular,  as  in  the  case  of  the  cilia  attached  to  the 
cells  of  the  respiratory  tract,  which  lie  flat  on  the  free 
surface  and  then  lash  forward,  serving  in  the  air  cells  to 
keep  the  air  in  motion  and  in  the  tubes  to  send  secretions 
from  below  upward  and  outward  and  to  keep  out  for- 
eign bodies.  Cilia  are  also  found  in  the  female  genital 
tract,  where  they  aid  the  passage  of  the  ovum  from  the 
ovary  to  the  womb.  They  act  together,  though  appar- 
ently not  governed  by  the  nervous  system.  As  in  the 
white  corpuscles  of  the  blood,  whose  motion  also  is  not 
muscular,  the  changes  that  take  place  in  ciliated  epithe- 
lium are  probably  about  the  same  as  those  in  muscular 
tissue,  that  is,  contractile. 

The  Blood. — To  most  of  the  tissues  just  described 
nourishment  is  brought  in  the  blood,  which  cir- 
culates through  the  body  in  a  system  of  hollow  tubes, 
the  arteries  and  veins,  whence  it  is  distributed  through 
the  agency  of  the  lymphatic  system.  There  are  no  blood- 
vessels, however,  in  the  epidermis,  epithelium,  nails, 
hair,  teeth,  nor  in  the  cornea  of  the  eye.  The  vessels 
that  carry  the  blood  from  the  heart  are  called  arteries, 
those  that  return  it  veins.  The  former  begin  as  large 
vessels  and  gradually  decrease  in  size;  the  latter  begin 
as  small  vessels  and  form  larger  and  larger  trunks  as 
they  approach  the  heart. 

The  arteries  have  three  coats:  1.  a  thin,  serous  coat, 
the  internal  or  intima;  2.  a  middle  or  muscular  coat,  and 
3.  an  external  coat  of  connective  tissue.  The  middle 
coat  is  the  thickest  and  is  the  one  that  prevents  the  walls 
from  collapsing  when  cut  across.  Except  in  the  cra- 
nium, each  artery  is  enclosed  in  a  sheath  with  its  vein 


28  GENERAL    STRUCTURE    OF    THE    BODY. 

or  veins,  the  venae  comites.  Usually  the  arteries  occupy 
protected  situations  and  are  straight  in  their  course. 
Where  a  vessel  has  to  accommodate  itself  to  the  move- 
ments of  a  part,  however,  it  may  be  curved,  as  in  the  case 
of  the  facial  artery  which  is  curled  on  itself  to  allow  for 
movements  of  the  jaw.  They  anastomose  or  communi- 
cate freely  with  one  another,  thus  promoting  equality  of 
distribution  and  pressure  and  making  good  circulation 
possible  even  after  the  obliteration  of  a  large  vessel. 

The  veins  have  three  coats  like  the  arteries,  but  they 
are  not  so  thick  and  the  muscular  coat  is  not  so  highly 
developed,  so  that  the  walls  collapse  when  cut  and  have 
no  elasticity.  There  are  constrictions  on  the  surface 
of  many  of  the  veins  due  to  the  presence  of  valves. 
These  valves  are  formed  of  semi-lunar  folds  of  the  lining 
membrane  and  are  arranged  in  pairs.  They  serve  to 
prevent  the  blood,  whose  circulation  in  the  veins  is 
sluggish,  from  flowing  back. 

There  are  two  sets  of  veins,  the  superficial  and  the 
deep,  which  communicate  with  each  other.  In  fact, 
all  the  veins,  large  and  small,  anastomose  very  freely, 
especially  in  the  skull  and  neck,  where  obstruction 
would  result  in  serious  trouble,  throughout  the  spinal 
cord,  and  in  the  abdomen  and  pelvis.  The  deep  veins 
accompany  the  arteries  in  their  sheath,  while  the 
superficial  ones  have  thicker  walls  and  run  between  the 
layers  of  the  superficial  fascia  under  the  skin,  terminating 
in  the  deep  veins.  In  the  skull  the  venous  channels 
take  the  form  of  sinuses,  formed  by  a  separating  of  the 
layers  of  the  dura  mater,  with  an  endothelial  lining  that 
is  continuous  with  that  of  the  veins. 

The  capillaries  are  intermediate  between  the  arteries 
and  the  veins,  the  final  division  of  the  arteries  and  the 
first  source  of  the  veins.  They  are  tiny  vessels  with 
but  a  single  coat,  continuous  with  the  innermost  coat 
of  both  arteries  and  veins  and  consisting  practically  of 
one  layer  of  cells  with  a  small  amount  of  connective  tis- 
sue between.  They  spread  in  a  great  network  through- 


GENERAL    STRUCTURE    OF    THE    BODY.  29 

out  the  tissues,  forming  plexuses  and  being  especially 
abundant  where  the  blood  is  needed  for  other  purposes 
than  local  nutrition,  as  in  the  secreting  glands.  Their 
diameter  is  so  small  that  the  red  corpuscles  have  to  pass 
in  single  file  and  may  even  then  be  squeezed  out  of  shape. 
As  they  have  no  muscular  tissue  in  their  walls,  they  have 
no  power  of  contracting.  Their  walls,  however,  like 
those  of  the  smaller  arteries  and  veins,  are  porous  and  by 
virtue  of  this  quality  they  play  an  important  part  in  the 
economy,  since  in  them  the  exchange  takes  place  be- 
tween the  tissues  and  the  blood. 

The  arteries  in  general  carry  freshly  oxidized  blood 
and  the  veins  blood  from  which  the  oxygen  has  been 
largely  used  up  and  which  contains  waste  material. 
In  the  pulmonary  system,  however,  the  case  is  re- 
versed, the  pulmonary  arteries  conveying  venous  blood, 
as  it  is  called,  from  the  heart  to  the  lungs  to  be  oxi- 
dized and  the  veins  returning  the  blood  after  it  has 
received  its  new  supply  of  oxygen. 

The  pumping  of  the  blood  through  the  arteries  is  as- 
sisted by  the  contractions  of  the  muscular  coat,  while 
the  elastic  tissue,  of  which  it  contains  a  certain  amount, 
gives  elasticity  to  the  walls  and  enables  them  to  stretch 
and  so  to  accommodate  the  larger  blood  supply  forced 
into  them  at  each  beat  by  the  heart.  The  walls  of  the 
veins  have  not  the  power  of  contracting  and  the  blood 
is  pushed  through  more  by  gravity  and  the  action  of  the 
arteries  than  by  any  action  of  their  own. 

The  walls  of  all  the  vessels  are  nourished  by  tiny 
blood-vessels  in  the  outer^  coat,  known  as  vasa  vasorum, 
and  the  nerves  that  regulate  the  action  of  the  arteries 
are  the  vasomotor  nerves  from  the  vasomotor  center 
in  the  medulla.  Sufficient  impulse  goes  from  this  cen- 
ter to  the  blood-vessels  all  the  time  to  keep  them  some- 
what contracted,  in  a  state  of  tone,  that  is,  which  is 
increased  or  diminished  as  the  blood  supply  is  to  be 
diminished  or  increased. 

Lymphatic  System. — The  lymphatic  system  also  ex- 


30  GENERAL    STRUCTURE    OF    THE    BODY. 

tends  throughout  the  body  and  consists  of  a  system  of 
channels,  spaces,  and  glands  very  closely  related  to  the 
circulatory  system  and  containing  a  fluid  called  lymph. 
There  are  three  principal  parts  to  the  system:  1.  the 
lymph  spaces,  which  are  open  spaces,  with  no  definite 
walls,  in  the  connective-tissue  framework  of  the  body, 
more  frequent  near  arteries  and  veins  and  especially  so 


FIG.  7. — Diagram  showing  the  course  of  the  main  trunks  of  the  absorbent 
system:  the  lymphatics  of  lower  extremities  (D)  meet  the  lacteals  of  the  intestines 
(LAC)  at  the  receptaculum  chyli  (R.C.),  where  the  thoracic  duct  begins.  The 
superficial  vessels  are  shown  in  the  diagram  on  the  right  arm  and  leg  (s),  and  the 
deeper  ones  on  the  left  arm  (D).  The  glands  are  here  and  there  shown  in  groups. 
The  small  right  duct  opens  into  the  veins  on  the  right  side.  The  thoracic  duct 
opens  into  the  union  of  the  great  veins  of  the  left  side  of  the  neck  (T).  (Yeo.) 

among  the  capillaries;  2.  the  lymph  capillaries  or  small 
vessels  which  connect  the  lymph  spaces;  and  3.  the 
lymphatic  vessels,  of  which  there  is  a  deep  and  a  super- 
ficial set,  the  latter  accompanying  the  superficial  veins 
on  the  surface  of  the  body,  the  former  accompanying 
the  deep  blood-vessels. 

The  lymph  spaces  are  generally  small,  though  there 


GENERAL    STRUCTURE    OF   THE    BODY. 


31 


are  some  large  serous  cavities,  such  as  the  abdomen, 
that  may  be  considered  as  extended  lymph  spaces. 

The  lymphatic  vessels  have  delicate,  transparent  walls, 
with  three  coats  like  the  arteries,  though  much  thinner, 
and  anastomose  even  more  freely  than  the  veins.  They 
have  a  beaded  appearance  due  to  the  presence  of  numer- 


a.l. 


FIG.  8. — Diagram  of  a  lymphatic  gland,  showing  afferent  (a.  Z.)  and  efferent 
(e.  Z.)  lymphatic  vessels;  cortical  substance  (C);  medullary  substance  (M)\  fi- 
brous coat  (c) ;  sending  trabeculse  (tr)  into  the  substance  of  the  gland,  where  they 
branch,  and  in  the  medullary  part  form  a  reticulum;  the  trabeculse  are  sur- 
rounded by  the  lymph  path  or  sinus  (Z.  s.),  which  separates  them  from  the 
adenoid  tissue  (Z.  h.).  (Sharpey.) 

ous  valves,  which  form  constrictions  on  their  surface. 
The  right  lymphatic  duct,  which  is  only  about  an 
inch  long,  drains  all  the  lymphatics  of  the  right  half  of 
the  upper  part  of  the  trunk,  the  head,  and  the  neck  ap- 
proximately, while  the  thoracic  duct  drains  those  of  the 
rest  of  the  body.  The  latter,  which  is  the  largest  vessel 
of  the  system,  begins  opposite  the  second  lumbar  ver- 


32 


GENERAL    STRUCTURE    OF   THE    BODY. 


tebra  with  a  bulb-like  reservoir  for  the  lymph  or  chyle, 
the  receptaculum  chyli,  and  extends  up  along  the  spi- 
nal column  for  a  distance  of  about  eighteen  inches  to  the 
seventh  cervical  vertebra,  where,  with  the  right  lym- 
phatic duct,  it  empties  into  the  left  subclavian  vein  at  its 
junction  with  the  internal  jugular,  thus  establishing  direct 
communication  between  the  lymph  spaces  and  the  ve- 
nous system.  The  orifices  of  both  vessels  are  guarded 
by  semi-lunar  valves  to  prevent  regurgitation  of  the 
blood. 

The  lymphatic  glands  are  small  oval  glandular  bodies 
and  occur  here  and  there  along  the  course  of  the  lymph- 


skin  reflected. 
Pectoralis  major. 
Central  group  of  glands 


Cephalic  vein. 


Basilic  vein. 
Intercostohumeral  nerve. 

Auxiliary  fascia. 
Long  thoracic  vein. 


FIG.  9.— Central  (superficial)  lymphatic  glands  of  the  axilla.     (After  Leaf.) 


atics.  Before  entering  one  of  them  the  vessel  breaks 
up  into  several  afferent  vessels  which  form  a  plexus 
within  and  then  emerge  again  as  several  efferent  vessels 
which  soon  unite  to  form  one  trunk.  These  glands  oc- 
cur chiefly  in  the  mesentery,  along  the  great  vessels, 
and  in  the  mediastinum,  axilla,  neck,  elbow,  groin,  and 
popliteal  space. 

The  lymph  varies  in  character  with  the  locality,  being 
a  little  thicker  and  more  opalescent  in  the  lacteals,  as 
the  lymphatics  of  the  small  intestine  are  called,  especi- 


GENERAL    STRUCTURE    OF   THE    BODY.  33 

ally  during  digestion,  when  fat  is  present.  Here  it  is 
called  chyle.  Otherwise  it  is  generally  a  clear,  trans- 
parent and  slightly  opalescent  fluid,  which,  owing  to 
the  presence  of  fibrin,  clots  when  drawn  from  the  body 
and  allowed  to  stand.  In  fact,  it  resembles  blood 
plasma  very  closely  in  composition  and,  as  it  also  con- 
tains a  certain  number  of  corpuscles  or  leucocytes  that 
just  correspond  to  the  white  corpuscles  of  the  blood, 
it  is  practically  blood  without  the  red  corpuscles. 
These  leucocytes  have  considerable  power  of  amoeboid 
movement  and  are  thought  by  some  to  play  an  im- 
portant part  in  the  absorption  of  food. 

Owing  to  intracapillary  pressure,  the  lymph  trans- 
udes into  the  lymph  spaces  and  bathes  the  tissues,  being 
carried  away  again  by  the  lymphatics.  The  amount  of 
transudation  is  determined  by  the  blood  pressure — the 
greater  the  pressure,  the  greater  the  amount  of  trans- 
udation— and  is  increased  by  some  organic  action  of  the 
cells  in  the  walls  of  the  vessels.  In  the  process  of  transu- 
dation a  certain  amount  of  solid  matter  goes  through  the 
wall  of  the  vessel  and  it  is  probable  that  certain  protein 
elements  can  be  carried  thus  from  the  blood-vessels  to 
the  lymphatics,  though  they  do  not  pass  through  the 
capillary  wall  as  readily  as  other  substances.  Some 
lymph  is  also  probably  formed  by  the  action  of  the  tis- 
sues themselves,  though  the  process  is  not  understood. 

All  muscular  movements,  active  or  passive,  includ- 
ing the  respiratory  movements,  tend  to  drive  the  lymph 
on  its  way  by  pressure,  the  valves  of  the  vessels  keep- 
ing it  from  flowing  back.  Moreover,  its  flow  is  from  the 
capillaries  to  the  veins  or  from  a  region  of  high  pressure 
to  one  of  less  pressure.  There  is  probably  also  some  con- 
traction in  the  walls  of  the  vessels  themselves,  and  the 
continual  formation  of  lymph  helps  to  drive  it  along.  If 
an  obstruction  to  the  circulation  occurs,  however,  back- 
pressure results  and  causes  too  great  transudation.  In 
that  event  a  limb  becomes  swollen,  pale,  and  generally 
cool.  It  pits  on  pressure,  the  pressure  driving  the  lymph 


34  GENERAL    STRUCTURE    OF   THE    BODY. 

out  and  there  being  no  circulation  to  bring  it  back. 
This  condition  is  called  oedema  and  occurs  in  liver, 
kidney,  and  heart  troubles,  being  generally  first  ob- 
served at  the  ankles.  In  ascites,  hydrothorax,  hydro- 
cephalus,  and  pericardial  and  pleural  effusions  the  fluid 
corresponds  to  lymph  in  its  composition  and  the  large 
amount  is  due  to  excessive  formation  of  the  fluid,  which 
is  normally  present  in  small  quantities. 

Lymph  gives  the  tissues  substances  from  the  blood 
that  they  need  and  carries  off  those  they  do  not,  whether 
waste  or  substances  of  use  to  other  tissues.  Because 
they  thus  absorb  certain  materials  not  needed  by  the 
tissues  and  convey  them  to  the  circulation,  the  lymph- 
atics have  also  been  called  absorbents.  Indeed,  lymph 
may  be  spoken  of  as  the  middleman  between  the  blood 
and  the  tissues. 

Another  function  of  the  lymph  is  to  lubricate.  Thus, 
the  synovial  fluid  of  the  joints  is  lymph  and  the  pleurae 
and  the  pericardium  contain  lymph  or  serum  to  reduce 
the  friction  between  the  adjoining  surfaces  as  much  as 
possible.  The  brain  and  spinal  cord  do  not  quite  fill 
the  cavities  of  the  cranium  and  the  spinal  column  but 
float  on  a  cushion  of  lymph,  the  cerebro-spinal  fluid. 
When  the  brain,  which  is  subject  to  increase  and  dimi- 
nution in  size,  increases  in  size,  it  drives  the  lymph  out, 
and  when  it  diminishes,  the  lymph  returns. 

The  lymph  glands  serve  as  a  protection  to  adjacent 
parts  and  when  it  leaves  the  gland  the  lymph  is  purer 
and  richer  in  leucocytes  than  when  it  entered.  In  fact, 
they  filter  harmful  matter  from  the  lymph  and  appar- 
ently also  form  white  corpuscles.  Normally  they  can 
with  difficulty  be  felt,  but  in  disease,  if  the  leucocytes 
are  unable  to  destroy  or  carry  off  the  poison,  the  lymph 
carries  it  along  to  the  glands,  which  swell  and  become 
tender.  If  the  infection  is  not  severe  the  swelling  goes 
down  and  the  tenderness  passes  after  a  short  time,  but 
if  it  is  severe,  there  may  be  suppuration  and  abscess  for- 
mation and  the  gland  even  perhaps  be' destroyed,  giving 


GENERAL    STRUCTURE    OF    THE    BODY.  35 

its  life  for  the  health  of  the  part.  Thus  a  wound  in  the 
foot,  if  infected,  may  cause  irritation  and  enlargement 
of  the  glands  at  the  knee  and  in  the  groin. 

The  lymphatic  glands  are  frequently  the  seat  of  tu- 
bercular infection,  especially  in  the  neck,  and  are  en- 
larged in  scarlet  fever,  tonsillitis,  and  diphtheria.  In 
syphilis  there  is  general  glandular  enlargement,  and  the 
glands  in  the  groin  become  enlarged  in  all  diseases  of 
the  genital  organs.  In  malignant  growths,  such  as  can- 
cer, the  extension  of  the  disease  is  often  along  the  lines 
of  the  lymphatics. 

Glands. — Of  glands  in  general  a  word  might  now  be 
spoken.  They  are  of  two  kinds,  excreting  and  secret- 
ing, and,  when  simple,  are  formed  by  the  folding  in  of 
a  free  surface,  as  in  the  case  of  the  salivary,  gastric,  and 
sebaceous  glands,  the  cells  at  the  gland  becoming  so 
modified  as  to  be  able  to  perform  the  function  of  excret- 
ing or  secreting.  In  racemose  glands  the  gland  is 
broken  up  into  many  pockets.  Excreting  glands  take 
from  an  organ  or  from  a  part  substances  which  have  out- 
lived their  usefulness  and  are  to  be  cast  out  of  the  body, 
while  the  secreting  glands  form  from  the  blood  sub- 
stances that  did  not  exist  in  it  before,  but  which  are  of 
use  to  the  body,  as  the  ptyalin  of  the  saliva.  A  strict 
line  cannot,  however,  be  drawn  between  the  two  kinds 
of  glands,  most  glands  partaking  more  or  less  of  both 
functions,  though  the  sebaceous  and  sweat  glands  are 
probably  purely  excreting  glands  and  the  salivary  glands 
are  almost  purely  secreting.  The  glands,  moreover, 
are  more  or  less  interchangeable  in  their  functions,  that 
is,  they  have  vicarious  function,  and  one  gland  can  take 
up  and  do  for  another  what  that  other  is  for  some  reason 
unable  to  do.  In  jaundice,  where  there  is  stoppage  of 
the  bile  duct,  the  kidneys  help  out  the  liver  by  excret- 
ing the  bile.  If  one  kidney  is  removed  the  other  does 
work  for  both,  and  the  glands  of  the  skin  may  help  out 
the  kidneys  or  vice  versa.  Hemorrhage  from  the  lungs 
sometimes  occurs  in  suppression  of  the  menses. 


36  GENERAL    STRUCTURE    OF   THE    BODY. 

In  a  general  way  the  function  of  glands  is  chemical. 
They  filter  out  by  osmosis,  selecting  the  useful  parts 
for  secretion  and  the  useless  for  excretion.  In  the  chem- 
ical action  that  goes  on  considerable  energy  is  given  off, 
as  is  shown  by  the  amount  of  pressure  in  the  glands  and 
by  the  fact  that  their  temperature  is  higher  than  that 
of  the  blood.  They  all  work  in  a  reflex  manner,  being 
under  the  control  of  the  central  nervous  system.  Thus, 
what  is  eaten  affects  the  nerve  terminals  in  the  mouth, 
the  sensation  passes  to  the  nervous  system,  and  an  im- 
pulse is  carried  by  the  motor  nerves  to  the  salivary 
glands. 

Most  of  the  glands  have  ducts  to  convey  away  their 
secretion  to  other  parts  of  the  body  or  to  send  excretions 
out  of  the  body,  but  there  are  also  ductless  glands,  which, 
though  they  seem  to  have  some  important  function  in  the 
process  of  metabolism,  are  not  well  understood.  Most  of 
them  seem  to  manufacture  some  substance  that  is 
absorbed  by  the  tissues  and  that  plays  an  important 
part  in  the  bodily  metabolism,  though  nothing  is  se- 
creted by  them  externally.  They  are  said  to  have  an 
internal  secretion,  whereas  the  glands  with  ducts  have 
an  external  secretion.  The  liver  has  both  forms  of  se- 
cretion, the  bile  which  is  sent  out  and  the  glycogen  that 
is  stored.  The  ductless  glands  are  the  thymus  and  thy- 
roid glands,  the  suprarenal  capsules,  and  the  pituitary 
body  in  the  brain. 

Nervous  Tissue. — Presiding  over  all  the  organs,  mus- 
cles, and  blood-vessels,  as  the  source  of  all  action  and 
all  sensation,  are  the  nerves.  Nervous  tissue  is  of  two 
kinds:  1.  the  gray  or  vesicular,  which  originates  im- 
pulses and  receives  impressions,  and  2.  the  white  or  fi- 
brous, which  conveys  impressions.  The  gray  matter 
consists  of  large  granular  cells  of  protoplasm  containing 
nuclei,  which  give  off  many  branches  or  dendrites. 
From  the  under  surface  there  usually  comes  one  main 
branch,  the  axis-cylinder  process.  These  processes 
sometimes  give  off  branches  and  sometimes  not,  but 


GENERAL   STRUCTURE    OF   THE    BODY. 


37 


they  form  the  nerve  fibers  and  carry  impulses  away  from 
the  nerve  cells.  The  cells  of  the  processes  are  elongated 
in  shape,  have  a  nucleus,  and  are  placed  end  to  end,  with 
a  definite  constriction  between  them. 

Each  axis-cylinder  process  is  surrounded  by  a  sheath 
called  the  medullary  sheath,  while  each 
nerve  fiber  consists  of  a  central  axis-cylin- 
der process  surrounded  by  the  white  sub- 
stance of  Schwann  and  enclosed  in  a 
sheath.  A  bundle  of  these  fibers  invested 
in  a  fibro-areolar  membrane  called  the 
neurilemma  constitutes  a  nerve,  and  of 
these  the  white  matter  is  formed.  The 
blood  supply  is  brought  by  minute  vessels, 
the  vasa  nervorum. 

The  nerves  of  the  cerebro-spinal  system 
preside  over  animal  life  and  have  to  do 
with  voluntary  acts,  while  those  from  the 
sympathetic  system  regulate  organic  life 
and  are  quite  independent  of  the  will. 
Both  sensory  and  motor  nerves  extend  all 
over  the  body,  accompanying  the  arteries 
in  a  general  way.  The  sensory  nerves 
end  on  the  surface  in  plexuses,  in  end 
bulbs  situated  in  the  papillae  of  the  skin, 
or  in  tactile  corpuscles,  these  last  occur- 
ring  more  especially  where  there  is  no  medullary  sheath 

,°  c,    neurilemma;    a, 

hair.     The  motor  nerves  end  peripherally  nucleus;  e,  node  of 

!  i  i      i    ,  mi  1    Ranvier.     (Leroy.) 

in  plexuses  or  by  end  plates.     The  central 
terminations  of  the  motor  nerves  and  the  terminations 
of  sensory  nerves  in  special  organs,  except  where  they 
end  in  a  cell,  are  not  well  understood. 

Like  muscles,  nerves  are  probably  never  at  rest,  for 
through  them  the  muscles  get  their  tone.  When  a  nerve 
acts,  no  heat  is  produced  and  there  is  no  change  in  the 
nerve  afterward,  as  there  is  in  muscle.  Probably  nerve 
impulse  is  the  transmission  of  physical  rather  than  chem- 
ical changes  along  the  fiber,  the  atoms  of  the  nerve  being 


38  GENERAL   STRUCTURE   OF   THE    BODY. 

set  in  vibration  and  the  vibrations  being  transmitted 
along  its  length.  Stimulation  is  produced  by  physical 
injury,  by  chemical  influence,  by  electricity,  by  heat, 
and  the  message  is  always  referred  to  the  nerve  termi- 
nation. Thus,  if  the  nerve  at  the  elbow,  over  the 
"crazy  bone,"  is  touched,  a  tingling  is  felt  in  the  fingers 
rather  than  at  the  point  of  pressure.  A  person  who  has 
had  an  arm  or  leg  amputated  will  frequently  speak  of 
his  fingers  or  toes  on  that  side  being  cold,  or  complain 
of  pain  in  them,  because  the  scar  below  the  point  of  am- 
putation tightens  around  the  nerves  and  pinches  them. 
It  is  through  the  nerves  that  people  get  in  touch  with 
the  outer  world  and  that  they  judge  of  size,  weight,  etc. 
All  careful  adjustment  of  the  muscles  is  under  the 
control  of  the  nervous  system. 


CHAPTER   II. 
THE  SKIN,  ITS  APPENDAGES  AND  ITS  FUNCTION. 

The  whole  exterior  surface  of  the  body  is  covered  by 
the  skin,  an  excreting  and  absorbing  organ,  which  serves 
as  a  protection  to  the  parts  beneath  and  is  also  the  or- 
gan of  touch.  It  has  two  layers,  a  superficial  and  a 

Hair. 


Hair  follicle. 
Sweat  gland. 

FIG.  11. — Vertical  section  of  skin. 

deep.  The  superficial  layer,  the  epidermis  or  cuticle, 
is  composed  wholly  of  epithelial  cells,  of  which  the  deep- 
est layer  is  columnar  and  moulded  upon  the  papillary 
layer  of  the  derma,  while  the  intermediate  layers 
are  more  rounded  and  the  surface  ones  flat.  The 
deepest  layer  also  contains  the  skin  pigment,  which 
causes  the  variation  in  shade  between  the  Indian,  the 
negro,  and  the  white  man.  Below  the  epidermis,  which 
is  chiefly  protective,  is  the  tough,  elastic,  and  flexible 
tissue  of  the  derma  or  true  skin,  in  which  are  vested 
most  of  the  activities  of  the  skin.  Its  surface  is  covered 
with  papillae,  which  are  more  numerous  in  the  more 
sensitive  parts.  Each  papilla  contains  one  or  more 
capillary  loops  and  one  or  more  nerve  fibers,  while  some 
terminate  in  an  oval  body  known  as  a  tactile  cor- 
puscle. Beneath  the  papillae  is  the  reticular  layer,  com- 
posed of  interlacing  bands  of  fibrous  tissue  and  contain- 

39 


40        THE  SKIN,  ITS  APPENDAGES  AND  ITS  FUNCTION. 

ing  blood-vessels,  lymphatics,  and  nerves,  as  well  as  un- 
striped  muscle  fibers  where  hair  is  present. 

At  the  apertures  .of  the  body  the  skin  stops  and  is 
replaced  by  mucoiis  membrane,  an  integument  of  greater 
delicacy  but  which  consists  fundamentally  of  the  same 
two  layers,  a  superficial,  bloodless  epithelium  and  a 
deep  fibrous  derma.  It  is  continuous  with  the  skin, 
but  is  much  redder  and  more  sensitive  and  bleeds 
more  easily.  The  passages  and  cavities  that  it  lines, 
unlike  those  lined  by  serous  membranes,  communicate 
with  the  exterior  of  the  body  and  are  for  that  reason 
protected  against  contact  with  foreign  substances  by 
mucus,  which  is  thicker  and  more  sticky  than  the 
lymph  that  moistens  the  endothelium  found  on  serous 
surfaces.  Mucous  membrane  is  found  in  the  alimentary 
canal,  the  respiratory  tract,  and  the  genito-urinary  tract. 
In  cavities,  like  the  stomach  and  intestines,  which  are 
subject  to  variations  in  capacity,  it  is  thrown  into  folds 
or  rugae.  The  mucus  is  secreted  by  small  glands  in  the 
membrane. 

Appendages  of  the  Skin. — The  skin  has  various  ap- 
pendages. On  the  dorsal  surface  of  the  last  phalanges 
of  the  fingers  and  toes  are  flattened  and  horny  modi- 
fications of  epithelium,  the  nails.  They  have  a  root 
embedded  in  a  groove  of  skin  by  which  they  grow  in 
length  and  a  vascular  matrix  of  derma  beneath  them 
which  gives  growth  in  thickness.  To  their  growth 
in  length  there  seems  to  be  no  limit. 

The  hairs  also,  which  occur  all  over  the  body,  ex- 
cept on  the  palms  of  the  hands  and  the  soles  of  the 
feet,  are  a  modification  of  the  epithelium.  Each  hair 
has  a  bulbous  root  springing  from  an  involution  in  the 
epidermis  and  derma  called  the  hair  follicle,  into  which 
one  or  two  sebaceous  glands  empty.  It  is  raised  by 
involuntary  muscle  fibers  and  grows  by  constant  ad- 
ditions to  the  surface  by  which  it  is  attached.  This 
growth  seems,  however,  to  be  limited,  and  when  its 
term  is  reached  the  hair  falls  out  and  is  replaced  by 


THE  SKIN,  ITS  APPENDAGES  AND  ITS  FUNCTION.        41 

another.     The  horny  epithelial  cells  that  go  to  form 
the  hair  contain  the  pigment  that  gives  it  its  color. 
Like  the  hairs,  the  sebaceous  glands  are  situated  in  all 
parts  of  the  body  except  the  palms  of  the  hands  and  the 
soles  of  the  feet.     They  lie  in  the  papillary  layer  and 


FIG.  12. — Skin  and  longitudinal  section  of  hair:  a,  Epidermis;  b,  corium;  c, 
sebaceous  gland;  d,  fibrous  root-sheath;  e,  glassy  membrane;/,  outer  root-sheath; 
g,  inner  root-sheath;  h,  expanded  bulbous  end  of  hair;  i,  papilla  of  hair;  ;', 
arrector  pili;  k,  adipose  tissue.  (Leroy) 

empty  into  the  hair  follicles,  except  occasionally,  when 
they  empty  directly  upon  the  surface  of  the  skin.  They 
secrete  an  oily  substance,  sebum,  the  debris  resulting 
from  the  degeneration  of  the  epithelial  cells  of  the 
gland  itself,  which  serves  to  keep  the  hair  glossy  and 
the  skin  soft  and  flexible. 


42        THE  SKIN,  ITS  APPENDAGES  AND  ITS  FUNCTION. 

The  sweat  glands,  on  the  other  hand,  are  more  fre- 
quent on  the  palms  and  soles  and  though  sometimes 
found  in  the  derma  are  usually  situated  lower  down  in 
the  subcutaneous  cellular  tissue.  They  are  least  nu- 
merous on  the  back  and  neck.  Coiled  up  in  the  lower 
layers  of  the  skin,  they  discharge  the  sweat  through  a 
spiral  excretory  duct  upon  its  free  surface. 

The  sweat  is  a  clear,  colorless,  watery  fluid  with  a 
salty  taste,  an  alkaline  reaction,  and  a  characteristic 
odor  that  varies  with  the  individual.  If  very  scanty, 
it  may  be  acid  in  reaction.  Besides  water  it  contains 
a  small  percentage  of  solids,  as  inorganic  salts,  especi- 
ally sodium  choloride,  fatty  acids,  neutral  fats,  and 
at  times,  especially  in  some  diseases  of  the  kidneys, 
urea,  that  is,  the  end-products  of  the  metabolism  of 
starches  and  fats  chiefly.  There  is  usually  also  some 
carbon  dioxide,  whence  the  expression  cutaneous  respi- 
ration. 

The  sweat  serves  to  keep  the  skin  moist  and  in  good 
condition,  to  remove  outworn  and  poisonous  or  ir- 
ritating matters,  and  to  regulate  the  temperature.  As 
a  rule  it  evaporates  upon  reaching  the  surface,  in  which 
case  it  is  known  as  invisible  or  insensible  perspiration, 
but  if  conditions  of  the  atmosphere  are  not  favorable 
to  prompt  evaporation,  as  when  the  air  is  damp,  the 
skin  becomes  damp  and  there  is  visible  perspiration. 

Though  an  abundant  supply  of  blood  increases  the 
action  of  the  sweat  glands,  they  are  regulated  by  defi- 
nite secretory  nerves  rather  than  by  the  vasomotor 
nerves.  In  a  cold  sweat  the  action  is  probably  due 
to  some  disturbance  of  the  nerve  supply  without  in- 
crease of  the  blood  supply.  Ordinarily  perspiring  is 
a  reflex  act  due  to  the  stimulation  of  the  afferent  cu- 
taneous nerves,  as  by  the  application  of  heat,  but  some- 
times, as  in  cases  of  strong  emotions,  involuntary  im- 
pulses are  sent  from  the  brain  to  the  spinal  centers  and 
so  arouse  the  action  of  the  glands.  Atropin  has  the 
power  of  preventing  the  secretion  of  sweat  by  paralyz- 


THE  SKIN,  ITS  APPENDAGES  AND  ITS  FUNCTION.        43 

ing  the  terminations  of  the  secretory  nerves,  while 
pilocarpin  produces  an  opposite  effect  in  a  similar  way. 

On  account  of  these  sweat  glands  the  skin  becomes 
next  in  importance  after  the  kidneys  in  the  excretion 
of  waste  products.  The  quantity  of  sweat  excreted 
varies  greatly  and  is  hard  to  measure.  It  is  influ- 
enced by  the  temperature  and  humidity  of  the  sur- 
rounding air,  by  the  nature  and  quantity  of  food  and 
drink  consumed,  by  the  amount  of  exercise,  the  rela- 
tive activity  of  other  organs,  especially  the  kidneys, 
and  by  certain  mental  conditions.  The  hotter  it  is, 
the  greater  the  amount  of  perspiration.  In  damp 
weather  there  may  be  less  perspiration,  but  it  does  not 
evaporate  and  is  therefore  more  in  evidence. 

Ordinarily  man  has  a  temperature  of  98.6°.  The 
source  of  this  body  heat  or  temperature  is  the  general 
body  metabolism,  muscular  activity,  and  activity  of 
the  glands,  especially  of  the  liver,  which  is  constantly 
active,  the  blood  in  the  hepatic  vein  being  warmer  than 
that  in  any  other  part  of  the  body.  The  tissue  of  the 
brain  also  is  said  to  be  warmer  than  the  surrounding 
blood,  and  the  heart  and  respiratory  muscles,  which 
are  in  constant  activity,  are  responsible  for  much  of 
the  body  heat.  The  amount  of  heat  generated  in  the 
body,  therefore,  varies  at  different  times,  according  as 
a  person  is  awake  or  asleep,  quiet  or  active. 

Temperature  Regulation. — The  temperature  is  reg- 
ulated by  variations  in  the  production  and  loss  of  heat, 
less  being  known  of  its  production  than  of  its  loss.  It 
has  been  calculated  that  four-fifths  of  the  energy  of 
the  body  is  converted  into  heat,  one-fifth  into  work. 
As  the  minimum  amount  of  heat  produced  in  twenty- 
four  hours  is  sufficient  to  raise  10  gallons  of  water  from 
0°  to  boiling-point,  it  is  evident  that  if  there  were  not 
some  way  for  the  escape  of  much  of  this  heat  the  body 
would  become  hotter  and  hotter  and  finally  destroy  itself. 
The  temperature,  however,  except  on  the  surface,  is 
uniform,  heat  being  lost  as  fast  as  it  is  produced.  For, 


44 

although  oxidation  at  any  point  raises  the  heat  of  the 
blood  at  the  point,  this  heat  is  carried  by  the  blood  to 
other  parts,  to  which  the  surplus  is  given  up,  while  blood 
cooled  in  the  skin  goes  to  the  hotter  inward  parts  to  cool 
them  and  be  warmed  itself.  In  fact,  heat  is  expended  by 
conduction  and  radiation,  through  respiration,  perspira- 
tion, and  heat  given  to  the  urine  and  faeces.  It  is, 
therefore,  largely,  75  to  80  per  cent.,  carried  off  through 
the  skin  and  the  lungs;  60  to  70  per  cent,  is  lost  by 
radiation  to  the  air  and  other  bodies  with  which  the  body 
comes  in  contact;  20  to  30  per  cent,  is  lost  by  the  evap- 
oration of  sweat,  4  to  8  per  cent,  by  the  warming  of  ex- 
pired air,  urine  and  feces,  and  1  to  2  per  cent,  by  cold 
food  that  is  taken  in.  Radiation  acts  more  favorably 
where  the  surroundings  are  cool  and  the  air  in  motion, 
as  on  a  breezy  day.  Conduction  is  carried  on  best  where 
the  surrounding  air  is  cool,  especially  if  it  is  moist,  for 
moist  air  is  a  better  conductor  of  heat  than  dry  air. 
Evaporation  is  very  important  in  hot  weather  or  where 
men  work  in  hot  air. 

Even  in  health  the  temperature  may  range  from  98.6° 
to  99.5°,  and  a  degree  or  two  below  or  above  is  not  danger- 
ous. When  a  person  first  gets  up  in  the  morning  his 
temperature  is  apt  to  be  subnormal,  but  after  food  and 
exercise  have  been  taken  it  becomes  normal  and  stays  so 
till  the  end  of  the  day,  when,  if  the  person  is  tired,  it  may 
go  up  a  little.  If  a  person  is  tired  out,  the  temperature 
is  apt  to  be  subnormal.  There  is  also  in  the  body  what 
is  called  the  vital  tide,  which  is  highest  afternoon  and 
evening  and  lowest  in  the  morning. 

The  rate  of  production  of  heat  varies  greatly  in  differ- 
ent people.  One  person  uses  a  certain  amount  of  tissue 
more  quickly  than  another,  that  is,  he  lives  faster.  More- 
over, size  makes  a  difference  in  that  a  small  body  has 
more  surface  to  its  weight  than  a  large  one  and  so  has 
to  produce  the  same  amount  of  heat  at  a  faster  rate  in 
order  to  maintain  the  right  temperature.  Taking  food 
increases  heat,  probably  because  of  the  muscular  effort 


THE  SKIN,  ITS  APPENDAGES  AND  ITS  FUNCTION.        45 

needed  to  eat  it.  Muscular  work  is  another  factor.  And 
finally  the  whole  matter  of  heat  production  seems  to  be 
under  the  control  of  the  nervous  system.  Not  much  is 
known  on  this  point  except  that  there  is  a  heat  center  in 
the  medulla  which  plays  an  important  part  in  heat  pro- 
duction and  whose  influence  is  seen  where  the  tempera- 
ture shoots  way  up  in  disease  just  before  death.  It  is 
now  thought  that  fever  is  due  to  a  disturbance  of  this 
nervous  mechanism,  though  just  what  the  disturbance 
is  is  not  known. 

Fever  is  a  condition  of  increased  bodily  temperature, 
due  to  increased  production  or  to  decreased  loss  of  heat. 
As  a  rule,  in  all  fevers  the  metabolic  changes  in  the  body 
are  increased.  Hence  the  patient  becomes  emaciated 
in  a  long  fever.  The  frequent  increase  in  the  amount  of 
urea  during  fever  shows  an  increase  in  protein  metabo- 
lism. The  temperature  in  fevers  rises  as  high  as  106° 
and  in  sunstroke  sometimes  to  110°.  Except  in  sun- 
stroke a  higher  temperature  than  106°  generally  means 
death.  Subnormal  temperature  is  due  to  a  decrease  in 
the  bodily  metabolism  and  so  to  lessened  heat  production. 
As  a  rule,  if  the  functions  are  all  active,  especially  that  of 
the  sweat  glands,  a  person  can  be  exposed  to  severe  heat 
without  the  temperature  being  affected,  though  some- 
times on  a  hot  summer  day  it  may  be  up  half  to  one 
degree.  The  cause  of  heat-stroke  with  its  high  fever  is 
unknown,  but  probably  it  is  due  to  some  effect  on  the 
heat  center  in  the  brain.  Heat  prostration  is  also  due 
to  prolonged  exposure  to  heat,  but  is  generally  accom- 
panied by  a  subnormal  temperature.  The  effect  of  cold, 
as  in  freezing,  is  to  diminish  all  the  metabolic  activities 
of  the  body.  The  temperature  can  be  artificially  regu- 
lated more  or  less  by  variations  of  food,  varying  amounts 
of  exercise,  by  drugs,  etc. 

Sense  of  Touch. — Before  passing  on  to  a  discussion  of 
the  individual  parts,  a  few  words  might  well  be  said  of  the 
sense  of  touch,  since  that  is  general  and  resides  largely 
in  the  skin,  whose  other  functions  have  just  been  de- 


46 

scribed.  It  may  be  regarded  as  the  form  from  which  all 
the  other  special  senses  have  developed,  certain  portions 
of  the  body  having  become  more  sensitive  than  others 
to  certain  vibrations,  as  the  eye  to  those  of  light.  The 
internal  organs  probably  have  little  sense  of  touch. 

Touch  is  useful  only  within  arm's  reach  but  there 
gives  one  a  sense  of  space  that  sight  does  not  give.  It  is 
practically  determined  by  the  touch  corpuscles,  which  are 
found  in  the  skin  over  almost  the  entire  body,  though 


.»v« :•*_-«_-. .1 Nerve  fiber. 

— j-  —    Nerve  fiber. 


Capsule. 

\«KV 

„_  Nerve  fiber. 

Nerve  fiber. 


FIGS.  13,  14. — Meissner's  corpuscle  from  man;  X750.     (Bohm,  Davidoff,  and 
Huber.) 

they  are  more  numerous  in  some  places  than  in  others, 
the  distribution  of  the  corpuscles  determining  the 
sensitiveness  of  the  skin.  These  touch  corpuscles  are 
protoplasmic  bodies  containing  nuclei,  about  which  are 
entwined  filaments  from  the  cutaneous  nerves.  Where 
the  corpuscles  are  absent  the  filaments  of  the  cutaneous 
nerves  themselves  play  an  important  part.  The  finger 
tips  have  a  very  delicate  sense  of  touch  and  the  tip  of  the 
tongue  is  the  most  sensitive  part  of  the  body.  Hence 
spaces  in  the  mouth  seem  larger  than  elsewhere.  By  the 


47 

transmission  of  sensations  of  touch  to  the  brain  the  sen- 
sation is  localized  and  the  tactile  sensation  becomes  a 
tactile  perception. 

There  are  three  main  divisions  of  the  sense  of  touch:  1. 
sensations  of  touch  proper  or  tactile  sensation;  2.  sen- 
sations of  temperature,  and  3.  sensations  of  pain.  The 
temperature  sense  is  the  transmission  by  the  skin  of  sen- 
sations not  so  much  of  a  certain  degree  of  heat  or  cold  as 
of  the  difference  between  the  temperature  of  an  object 
and  that  of  the  skin.  The  longer  an  object  is  in  contact 
with  the  skin,  the  less  conscious  the  person  is  of  it,  not 
only  because  it  becomes  of  the  same  temperature,  but 
also  because  he  becomes  accustomed  to  it.  There  also 
seem  to  be  in  the  skin,  besides  the  touch  corpuscles,  two 
other  terminal  organs  with  separate  nerve  fibers,  the  one 
for  detecting  heat,  the  other  cold;  for  there  are  places  on 
the  body  where  heat  can  be  detected  and  cold  cannot, 
and  vice  versa. 

Sensations  of  pain  may  be  merely  an  exaggeration  of 
tactile  sensation,  as  in  too  hard  pressure  or  too  great  heat, 
but  there  seems  to  be  also  a  sensation  of  pain  in  the  skin. 
All  organs  are  said  to  have  common  sensibility  to  pain 
and  any  exaggeration  of  this  sensibility  causes  a  sensa- 
tion of  pain.  All  the  special  senses  require  a  certain 
amount  of  judgment  in  the  interpretation  of  the  sensa- 
tions they  convey. 


CHAPTER  III. 
THE  CRANIUM  AND  FACE. 

The  intelligence  and  all  the  special  senses,  except  the 
sense  of  touch  already  spoken  of,  are  gathered  together 
compactly  in  the  head,  where  they  are  carefully  protected 
with  bony  tissue.  Covering  the  brain  is  the  skull  or  cra- 
nium, which  is  made  up  of  eight  bones,  the  frontal,  the 
occipital,  two  parietal,  two  temporal,  the  sphenoid,  and 
the  ethmoid,  while  the  bones  of  the  face  are  fourteen  in 
number,  two  nasal,  two  superior  maxillary,  two  lachry- 
mal, two  malar,  two  palate,  two  inferior  turbinated,  the 
vomer,  and  the  inferior  maxillary.  For  the  most  part 
the  bones  are  arranged  in  pairs,  one  on  either  side. 

The  Cranial  Bones. — The  cranium  or  skull  is  especially 
adapted  for  the  protection  of  the  brain  and  the  bones  are 
flat  and  closely  fitted  to  its  surface.  They  have  two 
layers  of  bone,  the  outer  and  the  inner  tables,  of  which 
the  outer  is  the  thicker,  and  between  these  is  a  tissue 
filled  with  blood-vessels,  the  diploe.  In  the  infant,  whose 
brain  has  not  yet  attained  its  full  size,  opportunity  must 
be  left  for  growth  and  the  skull  therefore  consists  of  a 
number  of  bones  with  interlocking  notched  edges,  where 
growth  takes  place,  but  in  the  adult  it  forms  one  solid 
covering  of  bone. 

The  line  where  the  edges  of  two  cranial  bones  come 
together  is  called  a  suture.  The  suture  between  the 
frontal  bone  and  the  forward  edges  of  the  two  parietal 
bones  is  called  the  coronal  suture,  that  between  the  two 
parietal  bones  at  the  vertex  of  the  skull  is  known  as  the 
longitudinal  or  sagittal  suture,  and  that  between  the 
occipital  bone  and  the  back  edges  of  the  parietal  bones 
as  the  lambdoidal  suture. 

48 


THE    CRANIUM    AND    FACE.  49 

Where  the  coronal  and  sagittal  sutures  meet  is  a 
membranous  interval  known  as  the  anterior  fontanelle, 
while  the  posterior  jontanelle  is  at  the  juncture  of  the 
sagittal  with  the  lambdoidal  suture.  These  fontanelles 
— so  called  from  the  pulsations  of  the  brain  that  can  be 
seen  in  them — close  after  birth  either  by  the  extension  of 
the  surrounding  bones  or  by  the  development  in  them 
of  small  bones  known  as  Wormian  bones ,  the  posterior 
one  closing  within  a  few  months,  the  anterior  by  the  end 


FIG.   15. — Cranium  at  birth,  showing  sutures  and  fontanelles. 

of  the  second  year.  In  rickets,  however,  the  anterior 
fontanelle  remains  open  a  long  time,  sometimes  into  the 
fourth  year. 

The  frontal  bone,  as  its  name  implies,  forms  the  fore 
part  of  the  head  or  forehead.  It  joins  the  parietal  bones 
above  and  the  temporal  bones  on  either  side.  At  the 
lower  edge  are  the  supra-orbital  arches,  each  with  a 
supra-orbital  notch  or  foramen  on  its  inner  margin  for 
the  passage  of  the  supra-orbital  vessels  and  nerve,  the 
nerve  most  affected  in  neuralgia.  Just  above  the 
arches  on  either  side  are  the  superciliary  ridges,  behind 
which,  between  the  two  tables  of  the  skull,  lie  the  frontal 
sinuses.  On  the  inner  surface  the  frontal  sulcus  for  the 
longitudinal  sinus  runs  along  the  median  line. 

The  parietal  bones  are  the  side  bones  of  the  skull. 
They  meet  each  other  in  the  sagittal  suture  at  the  median 

4 


50 


THE    CRANIUM    AND    FACE. 


line  above  and  join  the  frontal  and  occipital  bones  at 
either  end,  while  below  they  touch  upon  the  temporal 
bones,  the  temporal  muscles  being  attached  in  part  along 
their  lower  surface.  These  muscles  are  inserted  into  the 
coronoid  process  of  the  lower  jaw,  which  they  thus  help 
to  raise  and  to  retract. 

The  occipital  bone  is  at  the  base  of  the  skull  and  at 
birth  consists  of  four  pieces.     In  the  lower,  anterior  part 


FIG.  16. — Front  view  of  the  skull.     (After  Sobotta.) 

is  the  foramen  magnum,  an  oval  opening  through  which 
the  spinal  cord  passes  from  the  skull  down  into  the  spinal 
canal.  Half  way  between  the  foramen  and  the  top  of 
the  bone  is  the  external  occipital  protuberance  for  the 
attachment  of  the  ligamentum  nuchse  which  holds  the 
head  erect.  The  inner  side  of  the  bone  is  deeply  concave 
and  is  divided  by  a  cross-shaped  grooved  ridge  into  four 
fossae,  the  internal  occipital  protuberance  being  situated 


THE    CRANIUM    AND    FACE.  51 

where  the  arms  of  the  cross  meet.  The  occipital  lobes 
of  the  cerebrum  lie  in  the  two  upper  fossae  and  the  hemi- 
spheres of  the  cerebellum  in  the  two  lower  ones.  In  the 
grooves  upon  the  ridge  are  the  sinuses  which  collect  the 
blood  from  the  brain. 

The  occipital  and  frontal  muscles,  united  by  a  thin 
aponeurosis,  cover  the  whole  upper  cranium  and  are 
known  as  the  occipito-frontalis  muscle.  At  the  back  this 
is  attached  to  the  occipital  bone,  while  in  front  it  inter- 
laces with  various  face  muscles.  It  is  a  powerful  muscle 
and  raises  the  brows,  wrinkles  the  forehead,  and  draws 
the  scalp  forward.  Long  hair  grows  on  the  skin  over  it 
as  a  further  protection  against  blows  upon  the  skull  and 
sudden  variations  in  temperature. 

The  temporal  bones — said  to  be  so  named  because  the 
hair  over  them  is  the  first  to  turn  with  age — are  situated 
at  the  sides  and  base  of  the  skull  and  are  in  three  portions : 
the  squamous  or  scale-like,  the  mastoid  or  nipple-like, 
and  the  petrous  or  stony  portion.  The  squamous  is 
the  upper  portion  and  has  projecting  from  its  lower  part 
the  long  arched  zygomatic  process,  which  articulates 
with  the  malar  bone  of  the  face  and  from  which  arises  the 
masseter  muscle,  one  of  the  chief  muscles  of  mastication, 
'  which  has  its  insertion  in  the  ramus  and  angle  of  the  lower 
jaw.  Just  above  the  zygomatic  process  the  temporal 
muscle  has  its  origin  in  part,  while  below  is  the  glenoid 
fossa  for  articulation  with  the  condyle  of  the  lower  jaw, 
the  posterior  portion  of  the  fossa  being  occupied  by  part 
of  the  parotid  gland. 

The  rough  mastoid  portion  of  the  temporal  bone  is 
toward  the  back  and  affords  attachment  to  various  mus- 
cles, of  which  the  most  important  are  the  occipito- 
frontalis  and  the  sterno-cleido-mastoid.  Within  it  are 
the  mastoid  cells,  which  communicate  with  the  inner  ear 
and  are  lined  with  mucous  membrane  continuous  with 
that  of  the  tympanum.  They  probably  have  something 
to  do  with  the  hearing.  In  children  they  often  become 
the  seat  of  inflammation  (mastoid  abscess)  in  infectious 


52  THE    CRANIUM    AND    FACE. 

diseases  and  the  mastoid  bone  has  to  be  cut  to  let  out  pus 
that  has  collected.  As  the  lateral  sinus  is  directly  behind 
the  mastoid  bone,  there  is  very  great  danger  of  going 
through  into  the  sinus  and  causing  a  fatal  hemorrhage. 

The  petrous  portion,  which  contains  the  organ  of  hear- 
ing, is  between  and  somewhat  behind  the  other  two  por- 
tions, at  the  lower  edge  of  the  temporal  bone,  wedged 
between  the  sphenoid  and  the  occipital  bones.  On  its 
outer  surface  is  the  external  auditory  meatus,  and  from 


Vlrtlf 


FIG.  17.— Side  view  of  the  skull.     (After  Sobotta.) 

below  projects  a  long  sharp  spine  called  the  styloid  pro- 
cess, to  which  several  minor  muscles  are  attached.  In 
the  same  angle  between  the  petrous  and  squamous  por- 
tions lies  the  bony  Eustachian  tube. 

The  sphenoid  or  wedge  bone,  so  called  because  in  the 
process  of  development  it  serves  as  a  wedge,  lies  at  the 
base  of  the  cranium,  forming  as  it  were  the  anterior  part 
of  the  floor  of  the  cavity  containing  the  brain.  It  is  a 


THE    CEANIUM    AND    FACE.  53 

large,  bat-shaped  bone  and  articulates  with  all  the  cranial 
and  many  of  the  facial  bones,  binding  them  all  together. 
It  has  a  body,  two  large  wings,  and  two  lesser  wings  and, 
appears  on  the  outside  of  the  skull  between  the  frontal 
and  the  temporal  bones  behind  the  zygomatic  process. 
In  the  adult  the  body  of  the  sphenoid  is  hollowed  out  into 
the  sphenoid  sinuses,  in  which  pus  sometimes  forms. 

The  Ethmoid  Bone. — In  front  of  and  below  the  sphe- 
noid and  extending  forward  to  the  frontal  bone  is  the 
ethmoid,  the  last  of  the  cranial  bones.  It  consists  of  a 
horizontal  cribriform  or  sieve-like  plate,  from  either  side 
of  which  depend  lateral  masses  of  ethmoid  cells.  To 
the  inner  side  of  these  masses  are  attached  the  thin 
curved  turbinated  bones,  superior  and  middle,  while  be- 
tween them  is  a  vertical  plate  that  forms  the  bony  sep- 
tum of  the  nose.  •  Rising  from  the  upper  surface  of  the 
cribriform  plate  is  another  vertical  plate,  the  crista  galli, 
with  the  olfactory  grooves  on  either  side  for  the  reception 
of  the  olfactory  bulbs,  filaments  of  the  olfactory  nerve 
passing  down  through  the  perforations  of  the  cribriform 
plate  to  the  nose.  For  the  brain,  which  fills  almost  the 
entire  cavity  of  the  cranium,  is  supported  by  the  sphenoid 
and  ethmoid  bones  internally,  as  it  is  protected  externally 
by  the  other  cranial  bones. 

Ossification  of  Sutures. — If  premature  ossification  of 
all  the  sutures  occurs,  idiocy  results,  while  in  cephalocele 
there  is  a  gap  in  the  ossifying  of  the  bones  so  that  the 
membranes  or  brain  protrude.  In  rickets  the  forehead 
is  high  and  square  and  the  face  bones  poorly  developed, 
so  that  the  head  looks  larger  than  it  really  is.  In  Paget's 
disease  the  bones  enlarge  and  soften.  This  affects  the 
head  but  not  the  face  and  often  the  first  thing  noticed  is 
that  the  hat  is  too  small.  Craniotabes  is  thinning  of  the 
bone  in  places,  the  bone  becoming  like  parchment  and 
being  easily  bent.  It  is  generally  caused  by  pressure  of 
the  pillow  or  the  nurse's  arm. 

Bones  of  the  Face. — The  facial  bones  serve  to  form  the 
various  features  of  the  face,  which  after  all  are  merely 


54  THE    CRANIUM    AND    FACE. 

organs  of  special  sense.  Many  delicate  muscles  control 
the  facial  expression  which,  consciously  or  unconsciously. 
reflects  the  character  of  their  owner. 

Surgically  the  most  important  of  the  facial  bones  are 
the  two  superior  maxillary  bones,  because  of  the  number 
of  diseases  to  which  they  are  liable.  They  meet  in  front , 
together  forming  the  upper  jaw,  and  with  the  malar  bone 
help  form  the  lower  part  of  the  orbit  of  the  eye.  They 
are  cuboid  in  shape  and  are  hollowed  out  into  a  pyramidal 
cavity  called  the  antrum  of  Highmorc,  which  opens  by  a 
small  orifice  into  the  middle  nasal  meat  us  and  which 
sometimes  becomes  infected  and  has  to  be  tapped.  The 
nasal  process  for  articulation  with  the  frontal  and  nasal 
bones  has,  at  its  lower  edge,  a  crest  for  the  inferior  turbin- 
ated  bone,  and  close  beside  this  on  the  inside,  extending 
down  from  the  upper  edge,  is  a  deep  groove  which,  with 
the  lachrymal  and  inferior  turbinated  bones,  help- 
form  the  lachrymal  canal  for  the  nasal  tear  duct.  The 
bones  give  attachment  to  many  small  muscles,  connected 
for  the  most  part  with  the  nose  and  mouth,  of  which  the 
masseter  is  the  only  important  one. 

The  two  malar  or  check  bones  are  small  quadrangular 
bones,  which  form  the  prominences  of  the  cheeks  and 
help  form  the  orbits  of  the  eyes.  Projecting  backward 
from  each  is  a  zygomatic  process  for  articulation  with  the 
zygomatic  process  of  the  temporal  bone,  while  a  maxil- 
lary process  extends  downward  for  articulation  with  the 
superior  maxillary.  Here  again  the  most  important 
muscle  attached  is  the  masseter.  If  the  malar  boi; 
crushed  great  deformity  results. 

The  lachrymal  bones  are  two  small  bones,  about  the  size 
and  shape  of  a  finger-nail,  situated  at  the  front  of  the 
inner  wall  of  the  orbit.  At  the  external  edge  is  a  groove 
which  lodges  the  lachrymal  sac  above  and  forms  part  of 
the  lachrymal  canal  below. 

The  two  palate  bones  are  at  the  back  of  the  nasal 
and  help  to  form  the  floor  of  the  nose,  the  roof  of  the 
mouth,  and  the  orbit.     Each  has  a  vertical  and  a  hori- 


THE    CRANIUM    AND    FACE.  55 

zontal  plate,  and  it  is  these  last  that  by  their  juncture 
form  the  hard  palate.  Oftentimes  in  cases  of  hare-lip 
clejt  palate  also  occurs,  the  result  of  incomplete  develop- 
ment. To  remedy  the  consequent  opening  in  the  roof 
of  the  mouth,  which  makes  articulation  difficult,  opera- 
tion is  generally  resorted  to,  though  sometimes  a  plate 
is  fitted  over  the  opening  by  a  dentist. 

The  nasal  bones  are  two  small  oblong  bones  which 
articulate  with  the  frontal  and  superior  maxillary  bones 
and  with  each  other.  They  form  the  bridge  of  the  nose, 
the  rest  of  the  nose  being  wholly  of  cartilage,  except 
for  the  vomer,  a  bone  shaped  like  a  plough-share,  which 
forms  part  of  the  nasal  septum,  articulating  along  its 
anterior  edge  with  the  ethmoid  and  the  triangular 
cartilage. 

The  two  inferior  turbinated  bones  lie  along  the  outer 
walls  of  the  nasal  fossa?.  They  are  thin  scroll-like  bones 
covered  with  mucous  membrane  and  serve  to  heat  the 
air  as  it  passes  in.  Sometimes  when  one  has  a  cold,  the 
membrane  and  the  bone  too  swell  up  and  close  the  nares. 
Loss  of  the  sense  of  smell  in  a  bad  cold  may  be  due  to 
such  swelling  and  the  consequent  impeding  of  the  en- 
trance of  odoriferous  particles — a  condition  that  would 
likewise  interfere  with  the  sense  of  taste.  Part  of  the 
bone  is  sometimes  removed,  to  enlarge  the  passage, 
enough  being  left  to  warm  the  air. 

Lastly,  there  is  the  inferior  maxillary  bone  or  lower  jaw. 
This  has  a  horseshoe-shaped  body  and  two  rami,  one  at 
either  end.  Each  ramus  has  a  pointed  process  in  front 
called  the  coronoid  process,  into  which  is  inserted  the 
temporal  muscle.  At  the  back,  and  separated  from  the 
coronoid  process  by  the  sigmoid  notch,  is  the  condyle, 
which  articulates  with  the  glenoid  fossa  on  the  temporal 
bone.  The  rami  also  give  attachment  to  the  masseter 
muscle  at  its  point  of  insertion.  In  adult  age  the  ramus 
is  almost  vertical  but  in  old  age  the  portion  of  the  jaw 
hollowed  out  into  alveoli  for  the  teeth  becomes  absorbed 
and  the  angle  of  the  jaw  becomes  very  obtuse.  On  the 


56  THE    CRANIUM    AND    FACE. 

inner  side  of  the  jaw  near  the  middle  on  either  side  is  the 
fossa  for  the  sublingual  gland,  while  the  submaxillary 
gland  lies  in  a  fossa  farther  back  on  either  side. 

Sometimes  the  lower  jaw  is  dislocated  and  when  once 
this  has  occurred  it  is  liable  to  occur  again,  the  ligaments 
becoming  stretched. 


CHAPTER  IV. 
THE  ORGANS  OF  SPECIAL  SENSE. 

The  Nose. — The  nose,  the  organ  of  the  sense  of  smell, 
is  composed  of  a  framework  of  bones  and  cartilages,  the 
bridge  being  formed  by  the  two  nasal  bones,  and  the 
septum  by  the  vomer  and  the  triangular  cartilage.  It 
consists  of  two  parts,  the  external  nose  and  the  internal 
or  nasal  fossce,  which  open  to  the  face  by  the  anterior 
nares  or  nostrils  and  into  the  pharynx  by  the  posterior 
nares.  Externally  it  is  covered  with  skin,  internally 
with  ciliated  mucous  membrane.  The  jossce  have  the 


FIG.  18.— The  nasal  cavity.     (After  Sobotta.) 

inferior  turbinated  bones  along  their  outer  walls  and  are 
divided  into  three  parts  known  as  the  superior,  the 
middle,  and  the  inferior  meatus,  the  middle  one  connect- 
ing with  the  antrum  of  Highmore,  while  into  the  inferior 
meatus  the  lachrymal  canal  empties.  There  are  many 
small  muscles  of  which  little  use  is  made,  although  in 

57 


58  THE    ORGANS    OF    SPECIAL    SENSE. 

forced  respiration,  as  in  pneumonia,  where  every  aid  to 
breathing  is  called  into  play,  even  the  alse  nasi  or  nos- 
trils are  made  to  exert  what  muscular  power  they  pos- 
sess in  order  to  supply  more  air. 

Not  only  is  most  of  the  air  breathed  in  through  the  nose 
and  warmed  in  its  passage  through,  but  the  nose  is  the 
organ  of  smell  and  by  means  of  the  peculiar  property  of 
its  nerves  protects  the  lungs  against  deleterious  gases  and 
helps  the  taste  discriminate.  The  olfactory  or  first  cranial 
nerves,  after  emerging  from  the  brain,  lie  on  the  under  sur- 
face of  the  frontal  lobe  and  rest  on  the  ethmoid  bone  in 
what  is  known  as  the  olfactory  tract.  Each  nerve  ends 
in  a  bulb-like  termination  called  an  ol/actory  bulb,  which 
rests  on  the  cribriform  plate  and  sends  little  terminal 
fibers  down  through  to  be  distributed  to  the  nasal  cavities, 
especially  to  the  upper  half  of  the  septum  of  the  nose,  the 
roof  of  the  nose,  and  the  anterior  and  middle  turbinated 
bones.  For  in  the  mucous  membrane  of  the  upper  nasal 
cavity  are  specially  modified  epithelial  cells  called 
olfactory  cells,  which  play  an  important  part  in  the  con- 
duction of  smell.  Hence  when  one  wishes  to  smell  any- 
thing especially  well  he  sniffs  it  up. 

Probably  the  sensation  of  smell  is  caused  by  odorifer- 
ous particles  in  the  atmosphere  being  breathed  into  the 
nose,  where  they  affect  the  olfactory  cells,  which  transmit 
the  impulses  to  the  olfactory  nerve  and  so  to  the  brain. 
Whereas  a  certain  amount  of  moisture  in  the  nasal  cavity 
seems  to  be  essential  for  accuracy  of  smell,  the  presence  of 
too  much  or  too  little  interferes  with  it.  The  mucous 
membrane  has  a  certain  power  also  of  distinguishing 
different  smells  at  the  same  time,  though  this  power 
varies  greatly  in  different  people,  one  smell  often  wholly 
overpowering  all  others. 

The  cartilage  below  the  bridge  of  the  nose  is  sometimes 
attacked  in  syphilis  and  cancer,  and  lupus  often  begins 
on  the  nose.  Deviation  of  the  septum  may  occlude  all  air 
from  one  side  of  the  nose,  an  effect  also  produced  by 
polypi,  generally  of  the  turbinated  bone.  Either  condi- 


THE    ORGANS    OF    SPECIAL   SENSE.  59 

tion  is  easily  remedied.     Nosebleed,  though  generally  un- 
important, may  be  serious  in  adults. 

The  Mouth. — The  mouth  is  of  great  importance  as  an 
entrance  for  fresh  air  to  the  lungs  when  the  nasal  passages 
are  for  any  reason  impeded  and  as  the  resonant  chamber 
from  which  proceeds  the  voice,  man's  chief  means  of 
communication  with  his  fellows.  Its  chief  value  may  be 
said,  however,  to  reside  in  the  fact  that  it  is  the  vestibule 
of  the  alimentary  canal.  It  is  an  ovoid  cavity  lined  with 
mucous  membrane  and  is  bounded  in  front  by  the  lips, 
at  the  sides  by  the  cheeks,  below  by  the  floor  and  tongue, 


FIG.  19.— The  hyoid  bone.     (Toldt.) 

and  above  by  the  hard  palate  anteriorly  and  by  the  soft 
palate  posteriorly,  the  uvula  depending  from  the  latter 
like  a  curtain  between  the  mouth  and  the  pharynx. 
Shape  is  given  to  the  mouth  by  the  bones  of  the  upper 
and  lower  jaw  and  its -size  is  altered  by  the  lowering  and 
raising  of  the  latter,  which  is  quite  freely  movable. 

At  the  back  of  the  mouth,  at  the  entrance  to  the  phar- 
ynx, are  the  anterior  and  posterior  pillars  of  the  fauces, 
which  contain  muscular  tissue,  and  between  which  on 
either  side  are  thick  masses  of  lymphoid  tissue,  the  tonsils. 
The  floor  of  the  mouth  is  formed  largely  by  the  tongue, 
which  completely  fills  the  space  within  the  lower  teeth. 


60  THE    ORGANS    OF    SPECIAL   SENSE. 

Its  base  or  root  is  directed  backward  and  downward  and 
is  attached  by  muscles  to  the  hyoid  bone  and  the  lower 
jaw,  the  hyoid  bone  being  a  horseshoe-shaped  bone  lying 
just  below  and  as  it  were  within  the  inferior  maxillary. 
The  base  of  the  tongue  is  attached  also  to  the  epiglottis 
and  at  the  sides  to  the  soft  palate  by  the  anterior  pillars. 
Except  at  its  base  and  the  posterior  part  of  its  under 
surface  the  tongue  is  free,  but  a  fold  of  mucous  membrane, 
thefrenum,  holds  it  somewhat  in  front.  Thus  it  possesses 
great  versatility  of  motion  and  serves  as  an  auxiliary  in 
articulation,  mastication,  and  deglutition. 

The  Teeth. — Securely  embedded  in  either  jaw  are  the 
teeth,  nature's  instrument  for  the  first  preparation  of  the 
food  for  digestion  through  tearing  and  grinding.  The 
incisors,  which  are  in  front,  have  wide  sharp  edges  for 
cutting  the  food.  Next  come  the  canine  teeth  with  a 
sharp  point  for  tearing  it,  while  at  the  back  are  the  molars 
with  a  broad  flat  top  for  grinding. 

There  are  two  sets  of  teeth:  1.  the  temporary  or  milk 
teeth,  twenty  in  number — four  incisors,  two  canines,  and 
four  molars  in  each  jaw — which  appear  at  from  six 
months  to  two  years,  and  2.  the  permanent  teeth,  thirty- 
two  in  number — four  incisors,  two  canines,  known  as  eye 
teeth  in  the  upper  jaw  and  as  stomach  teeth  in  the  lower 
jaw,  four  bicuspids,  so-called  because  they  have  two 
cusps  where  the  molars  have  four  or  five,  and  six  molars 
in  each  jaw — which  come  from  the  sixth  to  the  twenty- 
first  years.  The  first  to  appear  are  the  two  lower  middle 
incisors,  which  come  at  the  age  of  six  months.  The  last 
to  appear  are  the  wisdom  teeth,  the  farthest  back  of  the 
molars,  which  come  at  the  age  of  twenty-one  years  or 
thereabouts. 

Each  tooth  consists  of  a  crown  or  body  above  the 
gum,  a  neck,  and  a  fang  or  root  within  the  gum.  The 
body  is  of  dentine  or  ivory  with  a  thin  crust  of  enamel 
and  contains  the  pulp,  a  vascular  connective  tissue 
containing  many  nerves.  Beginning  at  the  neck  and 
covering  the  fang  is  a  layer  of  cement  or  true  bone. 


THE    ORGANS    OF    SPECIAL    SENSE.  61 

The  Sense  of  Taste. — The  sense  of  taste  lies  chiefly  in 
the  taste  buds  as  they  are  called  which  are  filled  with 
gustatory  cells  and  are  found  in  the  papillae  of  the  tongue, 
principally  in  the  circumvallate  papillce  at  the  back  of  the 
tongue,  which  are  few  in  number  and  arranged  in  a  V- 
shape.  There  is  also  a  certain  power  of  taste  in  the  tip 
and  sides  of  the  tongue  but  little  in  the  upper  surface  or 
dorsum.  Only  five  special  tastes  can  be  distinguished: 
bitter,  sweet,  acid,  sour,  and  salt,  but  sometimes  more 
than  one  can  be  distinguished  at  a  time,  as  bitter  and 
sweet.  Every  one  can  distinguish  between  different 
tastes  but  the  power  varies  in  different  people  and 
with  different  conditions.  Certain  tastes  seem  to  be 
better  distinguished  in  certain  places,  as  sweet  at  the 
tip  and  bitter  at  the  back  of  the  tongue.  Moreover, 
the  sense  of  taste  is  very  dependent  upon  the  sense 
of  smell,  especially  in  the  case  of  aromatic  and  savory 
substances,  which  one  really  does  not  taste  but  smell. 
If  one  held  his  nose  and  closed  his  eyes  he  would  not 
know  from  the  taste  whether  he  was  eating  onion  or 
apple.  This  leads  to  the  habit  of  pinching  the  nose 
when  taking  nauseous  medicines. 

To  be  tasted  a  substance  must  be  in  solution.  Friction 
against  the  tongue,  lips  or  cheek  increase  the  sense  of 
taste.  A  temperature  of  100°  Fahrenheit  favors  taste, 
while  both  great  heat  and  great  cold  impair  it. 

There  are  probably  at  least  two  nerves  of  taste,  the 
lingual  branch  of  the  trifacial  or  fifth  cranial  and  the 
gustatory  branch  of  the  glosso-pharyngeal. 

Along  with  the  sense  of  taste  there  are  other  senses  in 
the  mouth  which  play  an  important  part,  such  as 
pressure  and  the  sense  of  heat  and  cold,  and  it  is  often  hard 
to  distinguish  them  from  the  pure  sensation  of  taste, 
which  indeed  is  always  accompanied  by  them. 

Salivary  Glands. — On  either  side  of  the  mouth  are 
three  racemose  glands  for  the  secretion  of  the  saliva, 
which  serves  to  soften  and  lubricate  the  food  and  parti- 
ally to  digest  starches  by  means  of  its  ferment,  ptyalin. 


62  THE    ORGANS    OF    SPECIAL    SENSE. 

The  parotid  gland  is  the  largest  and  is  below  and  in  front 
of  the  ear,  opening  by  Stensen's  duct.  The  submaxillary 
gland  is  below  the  jaw  toward  the  back  on  either  side 
and  its  duct  is  Wharton's  duct.  The  sublingual  gland  lies 
beneath  the  mucous  membrane  of  the  floor  of  the  mouth 
and  opens  by  eight  to  twenty  tiny  ducts  beside  the  fre- 
num,  the  ducts  of  Rivinus.  The  activity  of  the  glands 
depends  upon  the  blood  supply;  the  more  blood  the 
greater  their  activity. 


FIG.  20. — Dissection  of  the  side  of  the  face,  showing  the  salivary  glands:  a, 
Sublingual  gland;  b,  submaxillary  gland,  with  its  duct  opening  on  the  floor  of  the 
mouth  beneath  the  tongue  at  d;  c,  parotid  gland  and  its  duct,  which  opens  on  the 
inner  side  of  the  cheek.  (After  Yeo.) 

The  Tonsils. — The  tonsils  vary  in  size  and  in  tonsillitis 
swell  and  may  even  meet  in  the  median  line.  They  are 
frequently  removed.  When  they  are  enlarged  one  often 
gets  a  third  tonsil  or  adenoids,  a  lymphoid  growth  at  the 
back  of  the  pharynx  which  causes  mouth-breathing  by 
day  and  snoring  by  night.  A  child  with  adenoids  is 
starved  for  air  and  what  air  is  breathed  in  is  not  warmed. 
The  growth  should  be  removed. 

A  short  frenum  produces  tongue-tie,  which  may  be 
remedied  by  snipping.  Cancer  of  the  tongue  is  fairly 
common  and  necessitates  a  radical  operation.  In 
mumps  the  parotid  glands  are  inflamed  and  enlarged. 


THE    ORGANS    OF    SPECIAL    SENSE.  63 

The  Ear. — The  special  organ  of  hearing  is  the  ear,  to 
which  there  are  three  parts,  the  external,  the  middle, 
and  the  internal  ear. 

The  external  ear  consists  of  the  pinna  or  expanded  car- 
tilaginous portion,  for  the  concentration  and  direction 
of  sound  waves,  and  the  external  auditory  canal,  partly 
cartilage,  partly  bone,  which  is  directed  forward,  inward, 
and  downward  and  conveys  sound  to  the  middle  ear. 

The  middle  ear  or  tympanum  is  an  irregular  cavity  in 
the  petrous  portion  of  the  temporal  bone.  Its  outer  wall 
is  formed  by  the  membrana  tympani  or  drum,  an  oval 
translucent  membrane  placed  obliquely  at  the  bottom  of 


l-Os  articular*, 
CrLra., 

FIG.  21. — The  small  bones  of  the  ear;  external  view  (enlarged).      (After  Gray.) 

the  external  auditory  canal.  The  middle  ear  communi- 
cates with  the  inner  ear  through  the  fenestra  ovalis  or 
oval  window  and  contains  the  ossicles,  the  malleus  or 
hammer,  the  incus  or  anvil,  and  the  stapes  or  stirrup, 
which  are  arranged  in  a  movable  chain  from  the  drum  to 
the  oval  window.  The  malleus,  which  is  connected  with 
the  membrana  tympani,  articulates  by  its  head  with  the 
body  of  the  incus,  while  the  stapes  articulates  with  the 
incus  by  its  head  and  is  connected  by  its  base  with  the 
margin  of  the  oval  window.  Connection  is  made  be- 
tween the  middle  ear  and  the  pharynx  and  the  pressure 
of  the  air  upon  the  drum  made  equal  on  either  side  by 
means  of  the  Eustachian  tubes.  These  tubes  are  about 
an  inch  and  a  half  long,  have  cilia,  and  convey  wax  and 


64  THE    ORGANS    OF    SPECIAL    SENSE. 

other  matter  from  the  ear  to  the  pharynx.  Occasionally 
in  a  cold  or  for  some  other  reason  they  become  stopped 
up  and  trouble  results  in  the  middle  ear.  Some  of  the 
mastoid  cells  also  connect  with  the  middle  ear  and  may 
become  infected,  causing  mastoid  disease. 

The  internal  ear  consists  of  various  chambers  hollowed 
out  in  the  petrous  portion  of  the  temporal  bone.  There 
is  an  osseous  labyrinth,  consisting  of  a  central  cavity 
known  as  the  vestibule,  three  semicircular  canals,  and  the 
cochlea,  and  within  the  osseous  labyrinth,  surrounded  by 


FIG.  22. — Interior  view  of  left  bony  labyrinth  after  removal  of  the  superior 
and  external  walls:  1,  2,  3,  the  superior,  posterior,  and  external  or  horizontal 
semicircular  canals;  4,  fovea  hemi-elliptica  ;  5,  fovea  hemispherical  6,  common 
opening  of  the  superior  and  posterior  semicircular  canals;  7,  opening  of  the  aque- 
duct of  the  vestibule;  8,  opening  of  the  aqueduct  of  the  cochlea;  9,  the  scala 
vestibuli;  10,  scala  tympani;  the  lamina  spiralis  separating  9  and  10.  (From 
Quain,  after  Sommerring.) 

perilymph,  is  the  membranous  labyrinth,  of  like  form,  filled 
with  the  endolymph.  Communication  exists  externally 
with  the  middle  ear  by  the  round  and  oval  windows  and 
internally  with  the  internal  auditory  canal,  through  which 
passes  the  eighth  cranial  or  auditory  nerve,  the  special 
nerve  of  hearing,  which  is  distributed  to  the  inner  ear 
only.  When  the  auditory  nerve  enters  the  ear  through 
this  internal  auditory  meatus  it  divides  into  two  branches, 
of  which  one  goes  to  the  vestibule  and  the  other  to  the 


THE    ORGANS    OF    SPECIAL    SENSE.  65 

organ  of  Corti,  a  group  of  specially  modified  epithelial 
cells  in  the  cochlea  of  the  membranous  labyrinth,  which 
is  very  important  in  transmitting  the  impulses  to  the 
brain.  The  nerve  also  breaks  up  into  very  small 
branches  and  is  distributed  practically  throughout  the 
wall  of  the  labyrinth. 

The  sensation  of  hearing  is  the  result  of  impulses  trans- 
mitted to  the  auditory  nerve  and  so  conveyed  to  the 
auditory  center  in  the  brain.  It  is  caused  by  sound 
waves  which  travel  through  the  air  from  their  point 
of  origin  and  enter  the  external  ear.  This  collects  and 
selects  the  waves  of  sound  and  helps  one  to  a  certain 
extent  to  determine  the  direction  from  which  the  sound 
comes.  As  they  pass  through  the  external  meatus  the 
sound  waves  are  collected  into  a  comparatively  small 
area  for  transmission  to  the  middle  ear,  where,  by  means 
of  the  drum,  they  set  in  vibration  the  chain  of  ossicles. 
Through  these  the  vibrations  are  in  turn  transmitted 
to  the  oval  window,  being  intensified  in  the  process. 
Here  again  they  are  taken  up  by  the  perilymph,  from 
which  they  pass  through  the  wall  of  the  membranous 
labyrinth  to  the  endolymph,  affecting  the  epithelial 
lining  of  the  labyrinth  in  such  a  way  that  the  impulses 
are  transmitted  to  the  auditory  nerve,  more  particu- 
larly in  the  vestibule,  from  which  the  vibrations 
enter  the  cochlea.  They  also  affect  the  cells  of  the  or- 
gan of  Corti  in  like  manner  as  they  pass  from  the  peri- 
lymph  to  the  endolymph.  The  membrane  that  covers 
the  fenestra  rotunda  or  round  window  relaxes  and 
expands  as  the  vibrations  strike  it,  thus  serving  to 
eliminate  the  shock  of  impact. 

Musical  sounds  are  caused  by  rhythmical  or  regu- 
larly repeated  vibrations,  while  irregular  vibrations 
give  rise  to  noises.  In  musical  sounds  loudness  is  deter- 
mined by  the  height  or  amplitude  of  the  vibrations, 
pitch  by  the  length  of  the  wave,  and  quality  by  the 
number  of  so-called  partial  tones.  A  sensation  of  sound 
cannot  be  produced  by  less  than  30  vibrations  a  second 

5 


66  THE    ORGANS    OF   SPECIAL   SENSE. 

and  the  ordinary  person  cannot  hear  more  than  16,000 
vibrations  a  second.  Different  sounds  can  be  distin- 
guished when  they  follow  each  other  as  closely  as  by 
one  one-hundredth  of  a  second. 

All  sound  does  not  come  through  the  canal  of  the 
ear.  The  bones  of  the  head  vibrate  and  carry  sound. 
So  there  are  instruments  for  the  deaf  which  are  put  in 
the  ear  and  others  which  are  placed  between  the  teeth. 

The  semicircular  canals  are  not  essential  to  hearing 
but  have  something  to  do  with  a  person's  power  of 
maintaining  his  equilibrium.  Injury  to  them  may 
cause  dizziness  and  loss  of  equilibrium. 

The  Eye. — One  more  feature,  perhaps  the  most  ex- 
pressive, remains  to  be  described,  the  eye.  The  senses 
are  all  modifications  of  the  original  cutaneous  sensi- 
bility and  the  nerve  of  sight  is  no  more  sensitive  to  light 
than  any  other  nerve.  It  therefore  needs  an  end 
organ  that  is  sensitive  to  the  motions  of  the  ether  in 
order  to  give  impressions  of  light.  This  organ  is  pro- 
vided in  the  eye,  which  is  not  only  itself  capable  of  be- 
ing moved  in  every  direction,  but  is  placed  in  the  most 
movable  part  of  the  body,  the  head,  which  can  be 
turned  in  almost  a  complete  circle.  The  eyeball  is 
spherical  and  lies  in  the  cavity  of  the  orbit  upon  a  cush- 
ion of  fat,  where  it  has  a  large  range  of  sight  but  is 
securely  protected  from  injury  by  its  bony  surroundings. 
The  sunken  eyes  following  protracted  illness  are  due  to 
the  using  by  the  system  of  the  fat  on  which  the  eye- 
ball ordinarily  rests. 

Each  orbital  cavity  is  formed  by  the  juncture  of  some 
seven  bones  and  communicates  with  the  cavity  of  the 
brain  through  the  optic  foramen  and  through  the  sphe- 
noidal  fissure.  Above  the  orbits  are  arched  eminences 
of  skin,  the  eye-brows,  from  which  several  rows  of 
short  hairs  grow  longitudinally  and  which  serve  to  pro- 
tect the  eyes  and  to  limit  the  amount  of  light  to  a 
certain  extent,  as  in  frowning. 

Still  further  protection    is    afforded   by  the  eyelids, 


THE    ORGANS    OF    SPECIAL    SENSE. 


67 


longitudinal  folds  of  skin,  the  one  above,  the  other  be- 
low, which  close  like  curtains  over  the  eye.  Beneath 
the  external  layer  of  skin  in  the  lids  is  fatty  tissue  and 
then  the  orbicularis  palpebrarum  muscle  by  means  of 
which  they  are  closed.  They  are  kept  in  shape  by  the 
tarsal  plates  or  cartilages,  in  whose  ocular  surface  are 
embedded  the  Meibomian  glands,  whose  secretion  pre- 
vents the  free  edges  of  the  lids  from  sticking  together. 
Along  these  edges  grows  a  double  or  triple  row  of  stiff 
hairs,  the  eye-lashes,  which  curve  outward  so  as  not  to 
interfere  with  each  other  and  also  to  prevent  the  en- 
trance into  the  eye  of  foreign  bodies.  Lining  the 
inner  surface  of  the  lids  and  reflected  thence  over 


Levator  of   the  upper  eyelid 


Superior  rectus. 
External  rectus. 
Inferior  rectus. 


Superior  oblique. 
Internal  rectus. 

Inferior  oblique. 


FIG.  23.— The  external  ocular  muscles.     (Pyle.) 

the  anterior  surface  of  the  sclerotic  coat  of  the  eye 
is  a  mucous  membrane,  the  conjunctiva,  which  is  thick, 
opaque,  and  vascular  on  the  lids  but  thin  and  transpar- 
ent on  the  eye-ball.  The  angles  between  the  lids  are 
known  as  the  internal  a-nd  the  external  canthus. 

Muscles  and  Nerves. — The  eyeball  is  held  in  posi- 
tion by  the  ocular  muscles,  the  conjunctiva,  and  the 
lids,  while  surrounding  it,  yet  allowing  free  movement, 
is  a  thin  membranous  sac,  the  tunica  vaginalis  oculi. 
The  superior  and  inferior  recti  muscles  at  the  upper 
and  lower  edges  of  the  ball  turn  the  eye  up  and  down; 
the  internal  and  external  recti  at  the  inner  and  outer 


68  THE    ORGANS    OF    SPECIAL   SENSE. 

edges  turn  the  eye  inward  and  outward;  and  the  superior 
and  inferior  oblique  rotate  the  eye.  The  nerves  supply- 
ing these  muscles  are  the  third  or  motor  oculi,  the  fourth 
and  the  sixth. 

The  lachrymal  gland,  which  is  about  the  size  and 
shape  of  an  almond,  is  situated  at  the  upper  and  outer 
part  of  the  orbit.  It  secretes  a  fluid  which  keeps  the 
anterior  surface  of  the  eye  bathed  in  moisture  and  is 
ordinarily  drained  away  through  the  lachrymal  sac  in 
the  inner  canthus,  whence  it  passes  by  the  lachrymal 
ducts  into  the  nose.  When  the  amount  secreted  is 
excessive,  it  overflows  the  lower  lid  as  tears. 


Lacrimal  gland. 
Tarsal  cartilage. 

Nasal  or  tear-duct. 


Canaliculus. 
FIG.  24. — Diagram  of  the  lacrimal  apparatus.  (Pyle.) 

Coats  of  Eye. — The  membranes  or  coats  of  the  eye 
are  three  in  number:  an  outer  or  sclerotic,  a  middle  or 
vascular,  and  an  inner  or  sensitive. 

The  sclerotic  coat  is  a  rather  thick,  fibrous,  protect- 
ive membrane.  Where  it  passes  in  front  of  the  iris, 
however,  it  is  thinner  and  transparent  and  is  known 
as  the  cornea.  The  cornea  projects  somewhat  and,  as 
it  were,  resembles  a  segment  of  a  smaller  sphere  set  into 
the  rest  of  the  sclerotic. 

The  middle  or  vascular  coat,  known  as  the  choroid, 
carries  blood-vessels  for  the  retina  or  sensitive  coat  in 
its  inner  layer  and  has  an  outer  layer  of  pigment  cells 
that  excludes  light  and  darkens  the  inner  chamber  of 
the  eye.  The  folds  of  the  choroid  at  its  anterior  mar- 


THE    ORGANS    OF    SPECIAL    SENSE. 


69 


gin  contain  the  ciliary  muscles  and  are  known  as  the 
ciliary  processes,  while  the  name  iris  is  given  to  the  little 
round  pigmented,  perforated,  curtain-like  muscle  just 
in  front  of  the  crystalline  lens.  The  posterior  sur- 
face of  the  iris  is  covered  with  a  thick  layer  of  pig- 
ment cells  to  prevent  the  entrance  of  light  except 
through  the  central  opening  or  pupil,  and  its  anterior 
surface  also  has  pigment  cells  that  give  it  its  color, 
though  the  difference  in  the  color  of  people's  eyes  is  due 


Ocular  muscle. 


Retina. 


Sclera. 
Choroid.- 

Ciliary  muscle. 
Iris. 

Conjunc.  cul-de-sac. 

Ant.  chamber  and 

aqueous  humor. 

Crystalline  lens.  / 

Posterior  chamber. 

Angle  of  ant.  chamber. 

Suspensory  ligament 

of  the  lens. 


Cornea.  Vitreous  chamber. 

FIG.  25.— Vertical  section  through  the  eyeball  and  eyelids.     (Pyle.) 

rather  to  the  amount  of  pigment  present  than  to  its 
color,  a  small  amount  of  pigment  being  present  in  blue 
eyes  and  a  large  amount  in  brown  and  black  eyes. 
Variations  in  the  size  of  the  pupil  are  brought  about  by 
contractions  of  the  circular  and  radiating  fibers  of  the 
iris,  contraction  of  the  circular  fibers  making  it  smaller 
and  those  of  the  radiating  larger.  The  pupil  is  con- 
stricted for  near  objects  and  during  sleep,  and  is  dilated 
for  distant  objects.  In  a  dull  light  also  it  dilates  to  let 
in  more  light,  and  in  a  bright  light  it  contracts.  The 
appearance  of  the  pupil  is  often  important  as  a  means 
of  diagnosis  and  in  etherization. 

Lastly  there  is  the  innermost  sensitive  coat  or  retina, 
which  has  eight  layers,  the  outer  one  containing  some 
pigment  cells  and  the  next  the  rods  and  cones,  in  which 


70  THE    ORGANS    OF   SPECIAL   SENSE. 

the  power  of  perception  is  supposed  to  lie,  branches  of 
the  optic  nerve  being  distributed  over  it  in  all  directions. 
In  fact,  the  retina  is  formed  by  a  membranous  expan- 
sion of  the  optic  or  second  cranial  nerve,  the  special 
nerve  of  sight,  which  passes  into  the  orbit  through  the 
optic  foramen  at  the  back  and  enters  the  eye-ball  close 
to  the  macula  lutea  or  yellow  spot.  The  exact  spot  where 
the  optic  nerve  enters  the  retina  is  not  sensitive  and  is 
known  as  the  blind  spot.  In  the  center  of  the  macula 
lutea,  however,  which  is  in  the  middle  of  the  retina  pos- 
teriorly, is  a  tiny  pit,  the  fovea  centralis,  in  which  all 
the  layers  of  the  retina  except  the  rods  and  cones  are 
absent,  and  at  this  point  vision  is  most  perfect.  It  is, 
therefore,  always  turned  toward  the  object  looked  at, 
and  when  one  wishes  to  see  an  object  distinctly,  he  must 
keep  moving  his  eyes  over  it  that  the  rays  from  each 
part  may  fall  in  turn  upon  the  fovea  centralis. 

Directly  behind  the  pupil  is  the  crystalline  lens, 
a  rather  firm  gelatinous  body  enclosed  in  a  capsule, 
which  is  transparent  in  life  but  opaque  in  death.  The 
lens  is  doubly  convex  and  is  held  in  place  by  the  sus- 
pensory ligaments,  which  arise  from  the  ciliary  pro- 
cesses. In  front  of  it  is  the  anterior  chamber  of  the 
eye,  filled  with  a  thin  watery  fluid  called  the  aqueous 
humor,  while  the  larger  space  back  of  it,  occupying 
about  four-fifths  of  the  entire  globe,  is  filled  with  a 
jelly-like  substance  known  as  the  vitreous  humor. 

The  chief  artery  of  the  eye  is  the  ophthalmic. 

Light  Rays. — The  eye  is  practically  a  camera  and  its 
principal  function  is  to  reflect  images.  Although  there 
are  several  refracting  surfaces  and  media,  for  practical 
purposes  the  cornea  alone  need  be  considered.  Ex- 
cept for  those  rays  which  enter  the  eye  perpendicu- 
larly to  the  cornea,  whose  line  of  entrance  is  called  the 
optic  axis,  all  rays  are  refracted  when  they  enter  the  eye 
and  the  point  at  which  they  meet  and  cross  each  other 
behind  the  cornea  is  called  the  principal  focus  of 
the  eye.  To  focus  properly,  all  the  rays  from  any  one 


THE    ORGANS    OF    SPECIAL    SENSE. 


71 


point  on  an  object  must  meet  again  in  a  common  point 
upon  the  retina,  their  conjugate  focus.  In  the  normal 
eye  all  the  rays  from  an  object  are  focused  on  the  ret- 
ina and  form  upon  it  an  image  of  the  object  which,  as 
in  the  camera,  is  inverted,  because  of  the  crossing  of 
the  rays  behind  the  cornea.  Once  focused  on  the  ret- 


Fio.  26. — Diagram  showing  the  difference  between  (.4)  emmetropic,  (B)  myopic 
and  (C)  hypermetropic  eyes.     (American  Text-book  of  Physiology.) 

ina  the  light  traverses  the  various  layers  to  the  layer  of 
rods  and  cones,  where  chemical  action  takes  place  and 
affects  the  little  filaments  of  the  optic  nerve,  by  which 
the  message  is  carried  to  the  brain. 

When  the  eye  is  at  rest  the  pupil  and  lens  are  in  their 
normal  condition  and  at  such  times  the  eye  sees  only 


72  THE    ORGANS    OF    SPECIAL    SENSE. 

distant  objects.  The  ability  of  the  eye  to  focus  upon 
objects  at  different  distances  is  called  accommodation 
and  to  accomplish  it  three  things  are  necessary:  1. 
change  in  the  shape  of  the  lens;  2.  convergence  of  the 
axes  of  the  eyes,  and  3.  narrowing  of  the  pupils. 

When  the  eye  is  directed  toward  distant  objects,  the 
muscle  fibers  in  the  ciliary  processes  relax,  causing 
tightening  of  the  suspensory  ligaments  and  consequent 
flattening  of  the  surface  of  the  lens.  Otherwise  an  im- 
age would  be  formed  in  front  of  the  retina;  for  the 
greater  the  convexity  of  the  lens,  the  greater  the  angle 
of  refraction.  Such  accommodation  is  passive  and  so 
not  fatiguing.  To  look  at  nearby  objects,  on  the  con- 
trary, the  ciliary  muscles  contract,  drawing  the  cho- 
roid  forward  and  allowing  the  suspensory  ligaments 
to  relax,  so  that  the  lens  bulges  in  front.  This  is  an 
exertion. 

In  order  to  accommodate  properly,  moreover,  both 
eyes  must  work  together  and  the  axes  of  both  eyes  must 
be  directed  toward  the  object.  Therefore,  in  looking 
at  near-by  objects  the  axes  of  the  eyes  converge,  drawn 
by  the  internal  recti  muscles.  In  strabismus  or  cross 
eye,  where  the  axes  of  both  eyes  cannot  be  directed 
toward  the  object  at  the  same  time,  the  rays  fall  upon 
one  part  of  one  eye  and  upon  a  different  part  of  the 
other  eye  and  two  separate  images  are  seen. 

Finally  there  is  concentric  narrowing  of  the  pupil 
by  contraction  of  the  circular  fibers  of  the  iris,  by 
which  means  various  side  rays  that  would  come  to  a 
focus  outside  the  retina  are  excluded. 

All  the  muscles  of  accommodation,  the  ciliary  mus- 
cles, the  internal  recti,  and  the  spincter  pupillse,  are 
under  the  control  of  the  third  nerve. 

Connected  with  this  power  of  accommodation  and  de- 
pendent on  it  are  the  two  conditions  of  near-sighted- 
ness or  myopia  and  far-sightedness  or  hypermetropia. 

The  normal  eye  is  emmetropic  and  is  almost  per- 
fectly spherical,  but  in  the  near-sighted  or  myopic  eye 


THE    ORGANS    OF   SPECIAL    SENSE.  73 

the  ball,  instead  of  being  round,  is  flattened  from  above 
down  and  so  bulges  in  front.  Consequently,  owing  to 
the  greater  distance  from  the  lens  to  the  retina,  images 
are  formed  in  front  of  the  retina.  Only  nearby 
objects  can  be  seen  clearly,  because  the  farther  the 
object  from  the  eye  the  farther  in  front  of  the  retina 
the  image  is  formed.  Concave  glasses  are  worn  to  en- 
able near-sighted  people  to  see  at  a  distance.  Hyper- 
metropic  or  far-sighted  eyes  are  flattened  from  be- 
fore backward  and  can  see  only  objects  at  a  distance 
clearly,  as  those  nearby  form  images  behind  the  retina. 
For  such  eyes  convex  glasses  are  worn. 

As  the  ordinary  person  approaches  middle  life,  he  be- 
comes able  to  see  better  at  a  distance  than  near  to. 
This  presbyopia,  as  it  is  called,  which  is  practically 
far-sightedness,  is  due  to  a  partial  loss  of  the  power  of 
accommodation  in  the  lens,  the  result  of  a  general  loss 
of  elasticity  in  the  parts. 

Another  very  common  defect  is  astigmatism,  a  fail- 
ure of  the  rays  to  focus  upon  a  point,  owing  generally 
to  a  flattening  in  the  surface  of  the  cornea. 

Color  perception  is  also  an  important  function  of  the 
eye.  The  waves  of  hyperluminous  ether  when  of  a  cer- 
tain rate  of  vibration  give  the  sensation  of  heat  and 
when  their  vibrations  are  more  rapid  they  give  the  sen- 
sation of  light.  Each  of  the  primary  colors  of  the  spec- 
trum gives  off  a  pretty  definite  number  of  light  rays 
which  travel  through  the  air  and  enter  the  eye,  the  num- 
ber of  rays  determining  the  color  thrown  upon  the  ret- 
ina and  the  velocity  determining  the  intensity  of  the 
color.  Occasionally  when  light  is  passing  through  into 
the  eye  it  is  broken  up  as  in  a  prism  and  the  person  gets 
a  sensation  as  of  all  sorts  of  colors,  chromatic  aberra- 
tion. Total  or  partial  absence  of  sensitiveness  to  color 
is  called  color  blindness.  It  is  commonest  in  the  form 
of  inability  to  distinguish  between  red  and  green  and 
is  probably  due  to  a  defect  in  the  retina. 

Sometimes  a  hair  follicle  on  the  lid  becomes  infected 


74  THE    ORGANS    OF    SPECIAL    SENSE. 

and  a  sty  is  formed.  Pink  eye  is  conjunctivitis  or  in- 
flammation of  the  conjunctiva.  A  Meibomian  duct 
may  become  stopped  and  cause  bulging,  or  there  may 
be  a  sagging  down  or  ptosis  of  the  upper  lid  in  certain 
diseases,  as  meningitis,  apoplexy,  and  more  especially 
syphilis.  Rodent  ulcer  often  begins  by  the  eye  or  on  the 
cheek. 


CHAPTER  V. 
THE  NERVOUS  SYSTEM. 

The  nervous  system,  which  regulates  all  the  vital  pro- 
cesses of  the  body,  physical  and  chemical,  and  which  is 
situated  partly  in  the  head  and  partly  in  the  trunk,  may 
well  form  the  connecting  link  between  the  description  of 
the  head  and  that  of  the  trunk.  It  has  two  divisions, 
the  cerebro-spinal  system  and  the  sympathetic  system. 
The  former  consists  of  the  cerebrum  or  brain  proper,  the 
cerebellum  or  little  brain,  the  pons  Varolii,  the  medulla 
oblongata,  the  spinal  cord,  and  the  cranial  and  spinal 
nerves;  the  latter  of  a  series  of  ganglia  or  aggregations 
of  nerve  centers.  The  brain,  which  includes  the  cere- 
brum, cerebellum,  pons,  and  medulla,  occupies  the  cran- 
ium and  the  spinal  cord  is  contained  within  the  bony 
framework  of  the  spinal  column.  In  the  male  the  brain 
weighs  about  49  ounces  and  in  the  female  44,  while  in 
an  idiot  it  seldom  weighs  more  than  23  ounces. 

The  cerebrum  or  brain  proper  has  two  parts  or  hem- 
ispheres, roughly  oval  in  shape,  each  of  which  has  five 
lobes  separated  by  fissures,  the  frontal,  parietal,  occip- 
ital, and  temporo-sphenoidal  lobes,  and  the  central  lobe 
or  island  of  Reil  at  the  base  of  the  brain.  The  chief 
fissures  are  the  longitudinal  fissure,  the  fissure  of  Syl- 
vius at  the  base  of  the  brain,  and  the  fissure  of  Rolando 
between  the  frontal  and  parietal  lobes.  There  are  also 
five  serous  cavities  called  ventricles,  the  two  lateral  and 
the  third,  fourth,  and  fifth  ventricles,  of  which  the  first 
two,  one  in  either  hemisphere,  are  the  most  important. 
Around  these  cavities  is  the  brain  substance,  which  is 
made  up  of  two  tissues,  the  white  and  the  gray,  the  latter 
forming  the  outer  part  of  the  brain  to  the  depth  of 

75 


76  THE    NERVOUS   SYSTEM. 

perhaps  half  an  inch,  and  the  white  matter  forming  the 
rest.  The  outer  or  gray  part  is  called  the  cortex  and 
is  largely  made  up  of  nerve  cells.  It  might  be  called 
the  active  part  of  the  brain.  The  white  part  consists 
largely  of  nerve  fibers  which  are  given  off  from  the  nerve 
cells  and  are  carried  down  into  the  spinal  cord. 

The  surface  of  the  brain  is  convoluted,  the  ridges 
being  separated  by  deep  furrows  or  sulci,  by  which  means 
a  great  extent  of  gray  matter  is  secured.  The  furrows 
contain  fluid  from  the  subarachnoid  spaces  and  vary 
in  number  and  depth  according  to  intelligence.  While 
the  convolutions  are  not  uniform  in  all  brains,  the  prin- 
cipal ones  are  constant. 

Both  the  brain  and  the  spinal  cord  are  covered  by 
three  membranes,  the  dura  mater,  the  arachnoid,  and 
the  pia  mater.  The  dura  mater  is  dense  and  fibrous 
and  lines  the  interior  of  the  skull,  being  firmly  adherent 
to  it  at  many  points.  In  fact,  it  constitutes  the  internal 
periosteum  of  the  cranial  bones.  The  arachnoid  is  a 
delicate  serous  membrane,  with  two  layers,  lubricated 
to  prevent  friction,  which  divides  the  space  between 
the  dura  mater  and  the  pia  mater,  bridging  over  the 
convolutions  and  enclosing  the  subdural  and  subarach- 
noid spaces  which  are  connected  with  lymphatics  and 
contain  a  serous  secretion,  the  cerebro-spinal  fluid. 
This  fluid  forms  an  elastic  water  cushion,  on  which  the 
brain  rests,  and  prevents  concussion.  The  pia  mater 
is  vascular,  containing  blood-vessels,  lymphatics,  and 
nerves,  and  is  closely  attached  to  the  surface  of  the 
brain,  dipping  down  into  all  the  sulci. 

At  the  base  or  under  surface  of  the  brain  are  some 
very  important  structures.  The  olfactory  bulbs  lie  be- 
neath the  frontal  lobe  and  projecting  back  is  the  olfac- 
tory tract,  through  which  the  olfactory  nerves  come  from 
the  brain.  Back  of  the  olfactory  tract  is  the  optic  com- 
missure where  the  optic  nerves  coming  from  the  brain 
cross  each  other.  And  back  of  the  commissure  again 
is  the  optic  tract,  where  the  optic  nerves  emerge  from 


THE    NERVOUS    SYSTEM. 


77 


the  brain.     At  the  base  of  the  brain  are  also  the  exits 
of  the  twelve  cranial  nerves. 

Upon  entering  the  brain  the  arteries  run  a  tortuous 
course,  the  tortuosity  breaking  the  force  of  the  blood 


FIG.  27. — Base  of  brain.  (Leidy.)  1,  2,  3,  cerebrum;  4  and  5,  longitudinal 
fissure;  6,  fissure  of  Sylvius;  7,  anterior  perforated  spaces;  8,  infundibulum;  9, 
corpora  albicantia;  10,  posterior  perforated  space;  11,  crura  cerebri;  12,  pon8 
Varolii;  13,  junction  of  spinal  cord  and  medulla  oblongata;  14,  anterior  pyramid; 
14X,  decussation  of  anterior  pyramid;  15,  olivary  body;  16,  restiform  body;  17, 
cerebellum;  19,  crura  cerebelli;  21,  olfactory  sulcus;  22,  olfactory  tract;  23,  olfac- 
tory bulbs;  24,  optic  commissure;  25,  motor  oculi  nerve;  26,  patheticus  nerve; 
27,  trigeminus  nerve;  28,  abducens  nerve;  29,  facial  nerve;  30,  auditory  nerve; 
31,  glossopharyngeal  nerve;  32,  pneumogastric  nerve;  33,  spinal  accessory  nerve; 
34,  hypoglossal  nerve. 

stream  in  the  small  vessels  where  congestion  would  be 
with  difficulty  relieved.  The  basilar  artery,  which  is 
formed  by  the  juncture  of  the  two  vertebrals,  divides 
into  the  two  posterior  cerebrals,  each  of  which  joins  one 


78  THE    NERVOUS    SYSTEM. 

of  the  anterior  cerebrals  by  a  posterior  communicating 
artery.  The  two  anterior  cerebrals  also  are  joined  by 
an  anterior  communicating  artery,  thus  completing  the 
circle.  The  circle  thus  formed  at  the  base  of  the  brain 
is  called  the  circle  of  Willis  and  provides  for  a  good 
supply  of  blood  in  event  of  an  accident  to  any  vessel. 
The  blood  is  returned  to  the  general  circulation  through 
the  cerebral  veins  and  sinuses  formed  by  the  separation 
of  the  dura  mater  into  two  layers. 

The  cerebellum  is  about  one-seventh  the  size  of  the 
cerebrum  and  weighs  about  5  ounces.  It  lies  in  the 
lower  occipital  fossae  of  the  skull  and  is  oblong  in  shape 
and  divided  into  two  lateral  hemispheres  by  a  trans- 
verse fissure.  It  is  made  up  of  both  white  and  gray  mat- 
ter, of  which  the  former  predominates,  the  gray  being 
external  as  in  the  cerebrum.  The  cells  are  about  the 
same  as  in  the  cortex  and  its  surface  is  traversed  by 
queer  furrows.  Of  its  function  little  is  known  but  it 
probably  plays  a  most  important  part  in  the  coordi- 
nation of  the  nervous  and  muscular  acts  by  which  the 
movements  of  the  body  are  carried  on. 

At  the  back  of  the  cerebrum  and  below  the  cerebel- 
lum is  the  pons  Varolii,  which  forms  a  connecting  link 
with  the  medulla  oblongata  or  bulging  part  of  the  cord. 
It  is  made  up  essentially  of  white  matter  or  nerve 
fibers,  though  there  is  a  small  amount  of  gray  matter 
in  which  are  found  the  nuclei  of  some  of  the  cranial 
nerves. 

In  the  medulla  oblongata,  which  is  about  1  inch  long 
and  extends  from  the  pons  Varolii  to  the  upper  border 
of  the  atlas  or  first  cervical  vertebra,  the  gray  matter 
is  not  necessarily  external  to  the  white  but  is  found  in 
patches  in  the  white.  The  gray  matter  here  corresponds 
more  or  less  to  that  of  the  spinal  cord  and  the  white 
matter  is  continuous  with  that  of  the  cord.  From  the 
medulla  arise  the  fifth  to  twelfth  cranial  nerves  and  the 
vasomotor  nerves.  The  cardiac  nerve  has  its  center  here 
and  here  too  are  the  centers  of  respiration,  phonation, 


THE    NERVOUS   SYSTEM.  79 

deglutition,  mastication,  and  expression.  In  the  med- 
ulla the  nerves  that  arise  in  the  cerebrum  cross  over 
from  one  side  of  the  body  to  the  other  on  the  crossed 
pyramidal  tracts.  The  importance  of  this  crossing  of 
the  nerve  fibers  is  seen  in  apoplexy,  when  a  blood-vessel 
is  ruptured  in  the  brain  and  hemorrhage  causes  pres- 
sure, generally  on  the  motor  tract.  Paralysis  of  the 
nerves  and  of  the  muscles  to  which  they  go  results. 
The  paralysis  is  generally  of  one  side  of  the  body,  the 
opposite  side  from  that  on  which  the  injury  occurred. 
The  seat  of  injury  in  the  brain  or  cord  can  frequently 
be  determined  by  the  situation  and  extent  of  the 
paralysis. 

Spinal  Cord. — Extending  down  from  the  medulla 
through  the  spinal  column  is  the  cord.  Its  length 
from  the  foramen  magnum,  where  it  begins,  down 
through  the  vertebrae  to  the  lower  border  of  the  first 
lumbar  vertebra,  where  it  ends  in  a  very  fine  thread- 
like process  with  no  special  function,  called  the  filum 
terminate,  is  17  to  18  inches.  Just  before  it  ends  a 
number  of  nerves  are  given  off  in  a  tail-like  expansion 
known  as  the  cauda  equina  or  horse's  tail.  It  is  not 
uniform  throughout  its  length  but  presents  two  enlarge- 
ments, a  cervical  enlargement  in  the  lower  cervical  re- 
gion, and  a  lumbar  enlargement  in  the  lower  dorsal  re- 
gion, where  the  nerves  are  given  off  to  the  arms  and 
legs  respectively.  The  membranes  are  the  same  as 
those  of  the  brain  and  are  continuous  with  them,  but 
here  the  dura  mater  is  not  attached  to  the  bony  walls 
enclosing  it.  For  the  cord  does  not  fit  closely  into  the 
canal  but  is  as  it  were  suspended  in  it.  The  subarach- 
noid  space  communicates  with  the  ventricles  of  the 
brain  by  the  foramen  of  Majendie  and  is  filled  with 
cerebro-spinal  fluid  for  the  protection  of  the  cord.  In 
cerebro-spinal  meningitis  or  spotted  fever  this  fluid  is 
infected  and  for  diagnosis  lumbar  pucture  is  performed. 

If  a  cross-section  of  the  cord  is  made,  it  is  found  to 
have  a  pretty  definite  structure.  It  is  roughly  cir- 


80 


THE    NERVOUS    SYSTEM. 


cular  and  is  divided  by  certain  fissures,  of  which  the 
most  important  are  the  anterior  and  posterior  median, 
the  latter  being  rather  a  dividing  line  or  septum.  By 
them  it  is  divided  into  halves  connected  by  a  small 
band  in  the  middle  called  the  commissure.  The  white 
matter  is  exterior  to  the  gray  and  is  divided  by  it  into 
four  columns,  which  again  are  divided  into  tracts  ac- 
cording to  certain  groups  of  nerves  that  travel  through 


FIG.  28.— Different  views  of  a  portion  of  the  spinal  cord  from  the  cervical 
region,  with  the  roots  of  the  nerves.  In  A  the  anterior  surface  of  the  specimen 
is  shown,  the  anterior  nerve  root  of  its  right  side  being  divided;  in  B  a  view 
of  the  right  side  is  given;  in  C  the  upper  surface  is  shown;  in  D  the  nerve  roots 
and  ganglion  are  shown  from  below:  1,  the  anterior  median  fissure;  2,  posterior 
median  fissure;  3,  anterior  lateral  depression,  over  which  the  anterior  nerve  roots 
are  seen  to  spread;  4,  posterior  lateral  groove,  into  which  the  posterior  roots  are 
seen  to  sink;  5,  anterior  roots  passing  the  ganglion;  5',  in  A,  the  anterior  root 
divided;  6,  the  posterior  roots,  the  fibers  of  which  pass  into  the  ganglion,  6;  7,  the 
united  or  compound  nerve;  7',  the  posterior  primary  branch  seen  in  A  and  D  to 
be  derived  in  part  from  the  anterior  and  in  part  from  the  posterior  root.  (Allen 
Thomson.) 

them.  The  most  important  tract  is  the  direct  pyram- 
idal tract  in  the  anterior  column.  The  gray  matter  is 
arranged  in  the  form  of  a  letter  H  practically,  consist- 
ing of  two  lateral  halves,  more  or  less  crescentic  in  out- 
line, connected  by  a  narrow  band,  the  gray  commissure. 
Each  half  is  divided  into  two  horns,  the  anterior,  to- 
ward the  front  of  the  cord,  and  the  posterior,  toward 
the  back,  the  former  being  generally  much  thicker  and 
heavier  than  the  latter.  The  structure  of  the  gray  and 


THE    NERVOUS    SYSTEM. 


81 


of  the  white  matter  is  essentially  the  same  as  in  the 
brain,  but  the  proportion  varies  in  different  parts  of 
the  cord,  the  white  predominating  in  the  cervical  re- 
gion and  the  gray  being  much  better  developed  in  the 
lumbar  region,  where  the  nerve  cells  for  control  of  the 
lower  extremities  occur.  The  gray  is  least  well  devel- 
oped in  the  dorsal  region.  Through  the  center  of  the 
cord  runs  a  small  hole  or  canal  filled  with  cerebro-spinal 
fluid,  the  central  canal  of  the  cord. 


FIG.  29. — Functional  areas  of  the  cerebral  cortex,  left  hemisphere. 
(A.  A.  Stevens.) 

The  brain  is  the  seat  of  intelligence  and  will,  the  cen- 
ter of  all  voluntary  action.  Molecular  change  in  some 
part  of  the  cerebral  substance  is  the  indispensable 
accompaniment  of  every  phenomenon  of  conscious- 
ness. Indeed,  -the  brain  is  never  in  a  state  of  complete 
repose,  there  being  dreams  even  during  sleep.  The 
brain  is  not  sensitive  to  injury  in  the  sense  of  pain.  It 
can  be  lacerated  without  much  pain. 

Various  centers  exist  in  the  brain,  of  which  the  most 
important  perhaps  is  the  motor  center.  The  visual 
center  is  in  the  occipital  lobe,  the  auditory  center  in  the 

6 


82  THE    NERVOUS    SYSTEM. 

temporal  lobe,  the  speech  center  in  the  third  left  frontal 
convolution.  Thus  the  impulses  of  the  senses  have 
been  located,  though  the  function  of  many  parts,  the 
so-called  silent  areas,  are  still  in  obscurity. 

The  motor  center,  that  is,  the  center  for  motion  of  the 
skeletal  muscles,  is  situated  about  the  fissure  of  Rolando 
and  is  divided  into  three  parts,  one  for  the  legs,  one  for 
the  face,  and  one  for  the  arms,  the  one  for  the  legs  being 
uppermost  and  the  others  below  in  the  order  mentioned. 
Fibers  from  these  cells  extend  down  through  the  brain 
and  cord  to  the  muscles,  the  fibers  being  collected  into 
well-recognized  bundles  and  the  whole  known  as  the  motor 
tract.  There  may  be  one  long  fiber  from  a  cell  in  the 
brain  down  through  most  of  the  cord  or  there  may  be  a 
succession  of  shorter  fibers  that  are  not  actually  con- 
nected but  are  in  close  contact  with  each  other.  In  the 
upper  pons  the  fibers  for  the  face  cross  to  the  opposite 
side,  while  the  rest  keep  on  down  through  the  medulla, 
and  as  they  emerge  from  the  medulla  they  too  cross  to 
the  other  side  and  keep  on  down  in  the  crossed  pyramidal 
tract.  A  few  fibers  do  not  cross  but  come  down  the 
direct  pyramidal  tract,  which,  however,  disappears  part 
way  down.  The  crossed  pyramidal  tract  is  the  true  motor 
tract  and  in  it  the  fibers  are  continually  sending  branches 
to  the  cells  in  the  gray  matter,  where  they  connect  with 
the  anterior  horn. 

The  anatomy  of  the  sensory  tract  is  not  so  well  under- 
stood. By  it  impulses  are  sent  to  the  brain  by  the 
peripheral  organs,  practically  the  surface  of  the  body. 
The  sensory  fibers  connect  with  the  sensory  cells  in  the 
posterior  horn,  from,  which  fibers  are  sent  to  the  brain, 
practically  the  reverse  of  motor  action.  There  are 
three  chief  sensory  tracts,  which  are  supposed  to  trans- 
mit different  sensations,  one  pain,  one  muscular  sensa- 
tions, and  the  third  sensations  of  touch.  All  these 
tracts,  of  which  the  chief  is  the  direct  cerebellar  tract, 
in  passing  up  the  cord  pass  to  the  opposite  side  at  dif- 
ferent levels  and  then  go  on  to  the  cortex  of  the  brain. 


THE    NERVOUS   SYSTEM.  83 

The  action  of  the  nerves  is  similar  to  reflex  action,  only 
that  an  effort  of  will  is  needed  to  send  an  impulse  from 
the  brain.  It  is  by  the  help  of  the  brain  along  this  line 
that  an  infinity  of  artificial  reflexes  or  habits  is  acquired, 
for  which  volition  is  needed  in  the  beginning  but  which 
are  later  done  unconsciously.  Herein  lie  the  possibilities 
of  all  education. 

The  brain  and  spinal  cord  work  together,  the  cord 
acting  as  a  medium  between  the  brain,  in  which  all  the 
higher  psychical  processes,  such  as  will,  thought,  etc., 
originate,  and  the  muscular  apparatus.  The  cord, 
however,  has  some  action  entirely  independent  of  the 
brain,  as  is  seen  in  reflex  action.  This  action  is  entirely 
involuntary,  so  that  the  cord  is  sometimes  spoken  of  as 
the  seat  of  involuntary  action,  commonly  called  reflex 
action.  All  unconscious  acts  are  reflex  acts,  as  when 
the  hand  is  drawn  away  from  a  hot  iron.  If  an  impulse 
is  sent  along  one  of  the  sensory  fibers,  it  enters  the  cord 
through  the  posterior  horn,  where  its  nerve  cell  is  found. 
Then,  through  some  connection  between  the  nerve  cell 
of  the  sensory  fiber  and  that  of  the  motor  fiber  the  im- 
pulse is  transmitted  to  the  motor  cell  and  another  impulse 
is  sent  out  of  the  cord  along  the  motor  fiber  of  the  nerve 
to  the  muscle.  One  of  the  commonest  reflexes  is  the 
knee-jerk.  Reflex  action  is  important  because  the  re- 
flexes are  interfered  with,  delayed,  destroyed,  or  in- 
creased in  different  diseases.  The  time  normally  re- 
quired for  a  reflex  act  is  very  brief,  that  for  the  knee-jerk 
being  about  three  one-hundredths  of  a  second. 

The  nerves  of  the  head,  known  as  the  cranial  nerves, 
arise  from  the  brain,  while  the  rest  of  the  body  is  sup- 
plied by  the  spinal  nerves,  which  come  off  at  intervals 
from  the  spinal  cord.  The  cranial  nerves  consist  of 
twelve  pairs:  (1)  The  olfactory  or  nerve  of  smell,  (2) 
the  optic  or  nerve  of  sight,  (3)  the  motor  oculi,  (4)  the 
patheticus,  which  controls  the  eye,  (5)  the  trigeminus 
or  trifacial,  a  nerve  of  general  sensation,  motion,  and 
taste,  (6)  the  abducens,  a  motor  nerve,  (7)  the  facial 


84  THE    NERVOUS    SYSTEM. 

nerve  of  the  face,  ear,  palate,  and  tongue,  (8)  the  au- 
ditory or  nerve  of  hearing,  (9)  the  glosso-pharyngeal, 
nerve  of  sensation  and  taste,  (10)  the  pneumogastric 
or  vagus,  which  is  both  motor  and  sentory  and  governs 
respiration,  the  heart,  and  the  stomach,  (11)  the  spinal 
accessory,  to  the  muscles  of  the  soft  palate,  and  (12) 
the  hypoglossal,  the  motor  nerve  to  the  tongue. 

The  spinal  nerves  also  are  arranged  in  pairs:  Eight 
cervical  pairs,  twelve  dorsal  or  thoracic,  five  lumbar,  five 
sacral,  and  one  coccygeal,  these  titles  denoting  their 
point  of  origin  near  the  vertebra  of  the  same  name. 
Each  of  these  nerves  arises  by  two  roots,  an  anterior 
motor  root  from  the  anterior  horn  of  gray  matter  and  a 
posterior  sensory  root  from  the  posterior  horn,  the  latter 
having  a  ganglion  upon  it.  After  emerging  from  the 
cord  the  two  roots  unite  to  form  the  nerve,  that  the 
nerve  may  contain  both  motor  and  sensory  fibers.  The 
motor  fibers  are  called  efferent  because  they  carry  im- 
pulses from  the  cord,  while  the  sensory  are  called  afferent 
because  they  carry  impulses  back  to  the  cord.  After 
leaving  the  cord  the  nerves  unite  to  form  plexuses,  which 
again  divide  into  various  nerve  trunks  and  are  distrib- 
uted to  the  muscles. 

The  first  cervical  nerves  pass  out  of  the  spinal  column 
above  the  first  cervical  vertebra  and  the  other  cervical 
nerves  below  that  and  the  succeeding  vertebrae,  while 
the  other  spinal  nerves  emerge  each  below  the  corre- 
sponding vertebra,  as  the  first  dorsal  below  the  first 
dorsal  vertebra,  etc.  After  emerging  they  break  up 
into  a  large  anterior  division  and  a  small  posterior 
division,  the  posterior  branches  supplying  the  spine  and 
the  dorsal  muscles  and  skin,  the  anterior  the  rest  of  the 
trunk  and  the  limbs.  The  cervical  plexus  is  formed  by 
the  anterior  divisions  of  the  first  four  cervical  nerves, 
the  brachial  plexus  by  the  last  four  cervical  and  the  first 
dorsal  or  thoracic  nerves,  the  lumbar  plexus  by  the  four 
upper  lumbar,  and  the  sacral  plexus  by  the  last  lumbar 
and  the  four  upper  sacral  nerves. 


THE   NERVOUS    SYSTEM.  85 

The  only  important  branch  of  any  of  the  four  upper 
cervical  nerves,  which  in  general  supply  the  neck  and 
shoulders,  is  the  phrenic,  which  is  distributed  to  the 
pericardium,  the  pleura,  and  the  under  surface  of  the 
diaphragm. 

The  brachial  plexus,  as  its  name  implies,  supplies 
the  arms  and  has  a  number  of  important  branches,  as 
the  circumflex  to  the  shoulder,  the  musculo-cutaneous 
to  the  upper  arm,  the  elbow-joint,  and  the  outer  sur- 
face of  the  forearm,  the  internal  cutaneous  to  the  inner 
side  of  the  arm,  the  median  to  the  pronators  and 
flexors  and  the  fingers  on  the  radial  side,  and  the  ulnar 
to  the  elbow  and  wrist-joint.  The  musculo-spiral  runs 
down  the  spiral  groove  to  the  external  condyle  of  the 
humerus  or  upper  arm  bone,  where  it  divides  into  the 
radial  and  the  posterior  interosseous,  the  former  going 
to  the  thumb  and  two  adjacent  fingers  and  the  latter  to 
the  wrist-joint  and  the  muscles  on  the  back  of  the  fore- 
arm. Sometimes,  in  fracture  of  the  humerus  the  callus 
thrown  out  pinches  the  musculo-spiral  and  causes  pain. 

The  dorsal  or  thoracic  nerves  supply  the  back  with  their 
posterior  divisions  and  their  anterior  divisions  are  the 
intercostal  nerves. 

The  lumbar  nerves  supply  the  abdomen,  pelvis,  and 
thigh,  the  chief  branches  being  the  ilio-hypogastric  to 
the  abdomen  and  gluteal  region,  the  ilio-inguirial  to  the 
inguinal  region  and  scrotum,  the  external  cutaneous  and 
genito-crural  to  the  thigh,  and  the  obturator  to  the  thigh 
and  the  hip  and  knee-joints.  The  anterior  crural  de- 
scends beneath  Poupart's  ligament  and  divides  into  an 
anterior  and  a  posterior  division  which  supply  the  thigh 
muscles,  its  branches  going  to  the  pelvis. 

The  sacral  plexus  supplies  the  organs  of  the  pelvis, 
the  thigh,  and  the  leg.  Its  chief  branches  are  the  great 
sciatic,  the  largest  nerve  in  the  body,  and  the  small  sci- 
atic, which  go  to  the  buttocks  and  thigh.  The  great 
sciatic  runs  down  the  back  of  the  thigh  and  divides  at 
the  lower  third  of  the  thigh  into  the  internal  and  external 


86 


THE    NERVOUS    SYSTEM. 


popliteal  nerves,  the  former  of  which  passes  along  the 
back  of  the  thigh  to  the  knee,  where  it  becomes  the 


FIG.  30. — Diagrammatic  view  of  the  sympathetic  cord  of  the  right  side,  show- 
ing its  connections  with  the  principal  cerebro-spinal  nerves  and  the  main  preaortic 
plexuses.  (Reduced  from  Quain's  anatomy.) 

posterior  tibial,  which  in  turn  divides  at  the  ankle  into 
the  internal  and  external  plantar.     The  external  popli- 


THE    NERVOUS    SYSTEM.  87 

teal  descends  along  the  outer  side  of  the  popliteal  space 
and  divides  an  inch  below  the  head  of  the  fibula  into 
the  anterior  tibial,  which  supplies  the  flexors  and  skin 
of  the  ankle-joint,  and  the  musculo-cutaneous,  which 
sends  branches  to  the  skin  of  the  lower  leg  and  the  dor- 
sum  of  the  foot. 

The  Sympathetic  System. — Joined  to  the  cerebro-spinal 
system  by  intervening  cords  is  the  sympathetic  system. 
This  is  made  up  of  two  series  of  ganglia,  one  on  either 
side  of  the  spinal  column,  connected  by  longitudinal 
bands  and  extending  from  the  base  of  the  skull  to  the 
coccyx.  They  do  not  form  an  independent  nervous 
system,  each  ganglion,  which  seems  to  resemble  the 
motor  cells  of  the  spinal  cord,  being  connected  by  motor 
and  sensory  fibers  with  the  cerebral  system. 

The  sympathetic  nerves  are  mostly  gray,  non-medul- 
lated  fibers  and  are  distributed  to  viscera,  secreting 
glands,  and  blood-vessels,  whose  movements  are  in- 
voluntary and  feelings  obtuse.  They  form  networks 
upon  the  heart  and  other  viscera  and  send  branehes  to 
the  cranium  to  the  organs  of  special  sense.  There  are 
three  main  plexuses:  The  solar  plexus  behind  the  stom- 
ach, which  supplies  the  abdominal  viscera;  the  hypo- 
gastric  plexus  in  front  of  the  prominence  of  the  sacrum, 
whose  nerves  go  to  the  pelvic  organs;  and  the  cardiac 
plexus  behind  the  aortic  arch  for  the  thoracic  viscera. 

Over  these  nerves  one  has  no  control.  A  blow  in  the 
region  between  the  costal  cartilages  and  below  the  ster- 
num is  a  solar  plexus  blow  and  is  very  upsetting. 

The  sympathetic  system  serves  to  maintain  vitality 
in  all  the  important  portions  of  the  system  and  one  of 
its  important  functions  is  to  keep  up  communication 
between  one  part  and  another,  so  that  when  any  organ 
is  affected  the  others  will  act  accordingly  and  help  out 
to  the  best  of  their  ability. 


CHAPTER  VI. 
THE  BACK. 

The  Spine. — The  trunk  may  be  roughly 
divided  into  the  back,  the  chest  or  thorax, 
the  abdomen,  and  the  pelvis.  By  the 
back  is  denoted  the  spinal  column  with  its 
muscles,  blood-vessels,  etc.,  and  the  spinal 
cord  already  described.  The  spine  or 
vertebral  column,  which  serves  the  double 
purpose  of  holding  the  body  erect  and  of 
protecting  the  cord,  is  usually  about  two 
feet,  two  inches  in  length.  In  its  course 
there  occur  several  curves,  which  serve  to 
give  springiness  and  strength  and,  with 
the  intervertebral  cartilages,  to  mitigate 
the  force  of  concussion  from  blows  and 
falls.  The  curve  is  convex  forward  in  the 
cervical  region,  convex  backward  in  the 
dorsal,  forward  in  the  lumbar,  and  back- 
ward again  in  the  sacral  region.  There  is 
most  freedom  of  motion  in  the  cervical 
region. 

As  is  the  case  with  the  other  bones,  the 
vertebrae  are  specially  adapted  in  shape  and 
size  to  the  needs  they  are  called  upon  to 
fill.  Strength  and  flexibility,  with  a  mini- 
mum bulk,  a  channel  for  the  cord,  and 
passages  for  the  numerous  nerves  and 
blood-vessels  are  some  of  the  requirements 
which,  in  combination,  they  meet  to  an 
astonishing  degree.  They  are  thirty-three 
in  all,  and  are  divided  into  groups  according 
Fio  31  _The  to  the  region  in  which  they  occur:  seven  cer- 
spinai  column,  vical  in  the  neck,  twelve  dorsal  or  thoracic, 
'  five  lumbar,  five  sacral,  and  four  coccygeal. 
88 


THE    BACK.  89 

Although  the  vertebrae  of  the  different  groups  differ 
more  or  less  in  size  and  shape  in  accordance  with  the 
various  demands  of  their  positions,  they  all  have  certain 
general  characteristics.  Each  has  a  body,  two  laminae,  two 
pedicles,  two  transverse  processes,  and  one  spinous  pro- 
cess. The  pedicles  extend  back  from  the  body  on  either 
side  and  support  two  broad  plates  of  bone,  the  lamince, 
whose  juncture  at  the  back  completes  the  spinal  foramen 
for  the  passage  of  the  cord.  At  their  juncture  is  the 
spinous  process,  which  can  be  felt  beneath  the  skin,  while 
the  transverse  processes  project  from  the  juncture  of  the 


FIG.  32.— A  type   of  vertebra.     (Leidy.)     1,  Body;   2,   pedicle;  3,  lamina;  4, 
spinal  foramen;  5,  spinous  process;  6,  transverse  process;  7,  articular  process. 


laminae  with  the  pedicles.  All  the  processes  are  for  the 
attachment  of  muscles  that  move  the  spine.  The  body 
is  formed  of  cancellous  bone  with  a  compact  layer  outside. 
Transversely  it  is  slightly  oval, while  its  upper  and  lower 
surfaces  are  flat,  except  in  the  crevical  region,  where  the 
upper  surface  is  concave  laterally  and  the  under  convex 
laterally  and  concave  from  before  back.  Between  the 
bodies  are  disks  of  fibro-cartilage,  which  increases  motion 
and  springiness.  The  spinous  process  or  spine  is  short 
in  the  cervical  region,  long  and  directed  downward  in  the 
dorsal  region,  thick  and  projecting  almost  straight  out  in 
the  lumbar  region.  The  pedicles  are  notched  above  and 
below  so  that  when  articulated  the  notches  of  two  verte- 


90  THE    BACK. 

brae  join  to  form  the  intervertebral  foramen  for  the  out- 
ward passage  of  nerves  and  the  inward  passage  of  blood- 
vessels. 

The  distinguishing  mark  of  the  cervical  vertebra  is  the 
foramen  in  each  transverse  process,  through  which  the 
vertebral  arteries  run  to  the  skull.  They  are  also  smaller 
than  the  dorsal  and  lumbar  vertebrae.  The  dorsal  vertebra 
are  distinguished  by  having  on  the  transverse  processes 
and  on  the  body  smooth  articular  surfaces  called  facets 
and  demi-f acets  for  articulation  with  the  ribs.  The  lumbar 


FIG.  33.— The  sacrum,  from  before.     (Drawn  by  D.  Gunn.) 

vertebrce  are  the  largest  and  heaviest  and  have  the  thickest 
spine.  By  the  time  the  sacral  region  is  reached,  however, 
the  vertebrae  have  only  a  rudimentary  spinous  process. 
Moreover,  in  adult  age  the  sacral  bones  grow  together 
and  form  one  triangular  bone,  the  sacrum,  which  has  a 
broad  base  called  the  promontory  of  the  sacrum  and  a  blunt 
apex.  It  is  concave  in  front  and  convex  behind  and  has  an 
articulating  surface  for  joining  the  pelvic  bones.  In  the 
case  of  the  coccyx  also  the  four  original  bones,  all  rudi- 
mentary in  character  and  supposed  to  be  the  survival  of  a 
tail,  grow  together  to  form  one  bone.  Together  the  sacrum 
and  coccyx  form  the  posterior  wall  of  the  true  pelvis. 


THE    BACK.  91 

Some  of  the  dorsal  vertebrae  are  peculiar  in  the  arrange- 
ment of  their  facets  and  derm-facets,  while  among  the 
cervical  vertebrae  are  several  whose  peculiarities  should  be 
more  carefully  noted.  Thus,  the  first  cervical  vertebra 
or  a^as  supports  the  head  and  has  practically  no  body, 
the  place  of  the  body  being  taken  by  a  narrow  anterior 
arch  of  bone  and  an  opening,  continuous  with  the  spinal 
foramen,  into  which  the  odontoid  process  of  the  axis  fits, 
being  held  in  place  by  ligaments.  At  either  side  on  top 
is  a  facet  for  articulation  with  the  occipital  bone.  There 
is  almost  no  spine.  The  second  vertebra  or  axis  has 
surmounting  the  body  the  odontoid  process,  with  a  facet 
in  front  for  articulation  with  the  atlas  and  one  behind 
for  the  transverse  ligament  to  move  over.  The  seventh 
cervical  vertebra  or  vertebra  prominens  has  a  very  long 
spinous  process — hence  name — to  which  is  attached  the 
liyamentum  nuchce.  It  can  be  felt  very  distinctly  on 
the  living. 

Running  from  the  skull  down  through  the  spinal 
column  into  the  sacral  vertebrae  and  formed  by  the  join- 
ing of  the  spinal  foramina  of  the  individual  vertebras  is  an 
opening  called  the  spinal  canal,  which  holds  the  cord. 
The  cord,  however,  stops  practically  at  the  first  lum- 
bar vertebra,  where  it  splits  up  into  the  cauda  equina, 
only  the  filum  terminate  extending  farther  down. 

Occasionally  the  laminae  do  not  form  completely  and 
the  membranes  of  the  cord  may  bulge  out  and  form  a 
tumor,  or  the  cord  itself  may  come  out  also.  This 
generally  occurs  in  the  lumbar  region,  where  it  is  known 
as  spina  bifida.  If  in  case  of  fracture  of  a  vertebra  there 
is  paralysis  of  the  parts  below  due  simply  to  the  pressure 
of  a  fragment  of  bone  upon  the  cord,  it  may  be  completely 
cured  by  remoyal  of  the  fragment.  If,  however,  the 
cord  suffers  injury,  the  paralysis  will  remain.  Humpback 
or  Pott's  disease  is  caused  by  the  tubercle  bacillus,  which 
eats  away  the  bodies  of  the  vertebra?  so  that  the  column 
caves  in  and  the  spinous  processes  are  thrown  out  in  a 
hump  or  kyphos. 


92  THE    BACK. 

Muscles  of  the  Neck. — Before  speaking  of  the  muscles 
of  the  back  a  few  of  those  of  the  neck  had  best  be  taken 
up.  They  are  numerous  but  mostly  of  minor  importance. 
Largest  and  most  important  is  the  sterno-cleido-mastoid 
muscle,  which  has  its  origin  on  the  upper  part  of  the 
sternum  and  the  inner  third  of  the  clavicle  and  is  in- 
serted into  the  mastoid  process  of  the  temporal  bone. 
It  passes  obliquely  across  the  side  of  the  neck  and 


FIG.  34. — Muscles  of  the  right  side  of  the  head  and  neck:  1,  Frontalis;  2,  supe- 
rior auricular;  3,  posterior  auricular;  4,  orbicularis  palpebrarum;  5,  pyramidalis 
nasi;  6,  compressor  naris;  7,  leyator  labii  superiqris  alseque  nasi;  8,  levator  labii 
superioris;  9,  zygomaticus  major;  10,  orbicularis  oris;  11,  depressor  labii  in- 
ferioris;  12,  depressor  angulioris;  13,  anterior  belly  of  digastric  ;14,  mylohyoid; 
15,  hyoglossus;  16,  stylohyoid;  17,  posterior  belly  of  digastric;  18,  the  masseter; 
19,  sternohyoid;  20,  anterior  belly  of  omohyoid;  21,  thyrohyoid;  22,  23,  lower 
and  middle  constrictors  of  pharynx;  24,  sternomastoid;  25,  26,  splenius;  27,  leva- 
tor  scapulae;  28,  anterior  scalenus;  29,  posterior  belly  of  omohyoid;  30,  middle 
and  posterior  scalenus;  31,  trapezius.  (Borland's  Dictionary.) 

serves  to  flex  the  head  to  the  side  and  to  draw  the  face 
in  the  opposite  direction.  When  both  muscles  contract 
the  head  is  flexed  on  the  neck  and  the  neck  on  the 
chest.  In  wry  neck  or  torticollis  this  muscle  is  constantly 
contracted.  The  platysma  myoides  arises  from  the  fascia 
over  the  pectoral,  deltoid,  and  trapezius  muscles  and  is 
inserted  into  the  lower  jaw,  the  angle  of  the  mouth,  and 
the  loose  tissue  in  the  lower  part  of  the  face.  It 


THE    BACK.  93 

wrinkles  the  skin  of  the  neck  and  depresses  the  lower 
jaw.  In  the  cow  and  horse  it  is  so  highly  developed 
that  by  it  the  skin  can  be  contracted  all  over  the  body  to 
drive  off  flies.  The  rectus  capitis  anticus  major  arises 
from  the  third  to  the  sixth  cervical  vertebrae  and  is  in- 
serted into  the  occipital  bone,  serving  to  flex  the  head. 
The  scalenus  muscles  have  their  origin  on  the  lower  cer- 
vical vertebrae  and  are  inserted  into  the  first  and  second 
ribs,  thus  aiding  in  the  elevation  of  the  ribs  as  well  as  in 
lateral  flexion  of  the  neck.  The  head  is  held  upright  by 
the  ligamentum  nuchce,  which  rises  from  the  external 
occipital  protuberance  and  is  inserted  into  the  spinous 
processes  of  all  the  cervical  vertebrae  except  the  first. 

Muscles  of  the  Back. — The  chief  back  muscles  are  the 
trapezius  and  the  latissimus  dorsi,  which  together  cover 
in  the  back  pretty  thoroughly.  The  trapezius  arises 
from  the  occipital  bone,  the  ligamentum  nuchae,  and  the 
spinous  processes  of  the  seventh  cervical  and  all  the 
dorsal  vertebrae  and  is  inserted  into  the  outer  third  of  the 
clavicle  or  collar  bone  and  the  acromion  process  and  spine 
of  the  scapula  or  shoulder  blade.  It  is  thus  triangular  in 
shape  and  covers  in  the  neck  and  shoulders,  serving  to 
draw  the  head  back  and  to  the  side.  It  overlaps  the 
latissimus  dorsi. 

The  latissimus  dorsi  has  its  origin  by  aponeurosis  from 
the  spinous  processes  of  the  six  lower  dorsal  and  all  the 
lumbar  and  sacral  vertebrae,  from  the  crest  of  the  ilium  or 
hip  bone,  and  from  the  three  or  four  lower  ribs,  swings 
across  the  side,  dwindling  in  size,  and  is  inserted  by  a 
small  tendon  into  the  bicipital  groove  of  the  humerus  or 
upper  arm  bone,  thus  covering  in  the  part  of  the  back 
not  covered  by  the  trapezius.  It  draws  the  arm  down 
and  back,  raises  the  lower  ribs,  and  draws  the  trunk  for- 
ward, as  in  climbing.  The  flat  muscles  of  the  back  and 
abdomen  have  a  tendency  to  flatten  out  into  aponeuroses, 
such  as  occurs  in  the  origin  of  the  latissimus  dorsi. 

The  levator  scapulas,  from  the  transverse  processes  of 
the  upper  cervical  vertebrae  to  the  posterior  border  of  the 


94 


THE    BACK. 


scapula,  serves  to  raise  the  angle  of  the  scapula,  and  the 
rhomboideus  major  and  minor,  from  the  ligamentum 
nuchae,  the  seventh  cervical,  and  the  upper  dorsal  verte- 


FIG.  35. — Muscles  of  the  trunk  from  behind  (left  side,  superficial;  right  side, 
deep):  1,  Sternomastoid ;  2,  splenius;  3,  trapezius;  4,  latissimus  dorsi;  5,  infra- 
spinatus;  6,  teres  minor;  7,  teres  major;  8,  deltoid;  9,  external  oblique  of  abdomen; 
10,  gluteus  medius;  11,  gluteus  maximus,  12,  levator  anguli scapulae;  13,  rhomboi- 
deus minor;  14,  rhomboideus  major;  15,  part  of  longissimus  dorsi;  16,  tendons  of 
insertion  of  iliocostalis;  17,  supraspinatus;  18,  inf raspinatus ;  19,  teres  minor;  20, 
teres  major;  21,  serratus  magnus;  22,  upper,  and  22',  lower  part  of  serratus  posti- 
cus  inferior;  23,  internal  oblique;  24,  gluteus  medius;  25,  pyriformis  and  superior 
and  inferior  gemelli;  26,  26',  portions  of  obturator  interims;  27,  tendon  of  obtu- 
rator in  tern  us;  28,  quadratus  femoris.  (Borland's  Dictionary.) 

brae  to  the  root  of  the  spine  of  the  scapula,  draw  the  in- 
ferior angle  back  and  up. 

The  blood  supply  in  the  cervical  region  and  about  the 
shoulders  comes  from  branches  of  the  subclavian  artery, 
such  as  the  suprascapular  and  the  transversalis  colli. 


THE    BACK.  95 

Lower  down  the  supply  comes  from  the  posterior 
branches  of  the  intercostals,  dorsal  branches  of  the  lum- 
bar, and  branches  of  the  internal  iliac. 

The  muscles  of  the  back  are  supplied  by  the  spinal 
nerves,  the  spinal  accessory  also  going  to  the  trapezius 
muscle. 


CHAPTER  VII. 
THE  CHEST. 

The  chest  or  thorax  occupies  the  upper  part  of  the 
trunk  in  front  and  is  a  dome-shaped  cavity  containing 
and  protecting  the  heart  and  lungs.  Its  walls  are  formed 
by  the  dorsal  vertebrae  at  the  back,  the  ribs  at  either  side, 
and  the  sternum  and  costal  cartilages  in  front,  all  well 

Circumference  of  apex  of  thorax. 


First  rib. 

Second  rib. 

Third  rib. 


Seventh  rib. 

Eighth  rib. 

Ninth  rib.- 
Tenth  rib 

Eleventh  rib, 


Manubrium 
sterni. 


Costal  cartilages. 
Gladiolus. 


Ensiform  carti- 
lage or  xiphoid 
appendix. 


Eleventh  rib. 


Circumference  of  base. 
FIG.  36. — Thorax  (anterior  view.)     (Ingals.) 

covered  with  muscles.  The  floor  is  formed  by  the 
diaphragm.  Through  the  upper  opening  of  the  chest 
pass  the  trachea,  the  esophagus,  and  many  important 
vessels  and  nerves. 

The  shape  of  the  chest  may  vary  in  disease.     Thus,  in 

96 


THE    CHEST. 


97 


rickets  there  is  the  prominent  "pigeon"  breast  and  the 
rosary,  that  is,  a  bead  at  the  juncture  of  each  rib  with 
the  costal  cartilage,  while  in  emphysema  the  chest  is 
enlarged  in  all  directions  and  barrel-shaped.  In  severe 
cases  of  lateral  curvature  it  is  distorted  but  may  be  im- 
proved by  exercises. 

The  Sternum. — The  sternum  or  breast-bone  is  a  long 
narrow  bone  and  has  three  parts,  the  manubrium  or  han- 
dle above,  the  gladiolus  or  sword,  and  the  ensiform 
cartilage  at  the  lower  end.  On  either  side  are  notches 
for  the  costal  cartilages;  for  the  first  seven  ribs  as  well  as 
the  clavicle  articulate  with  it.  Except  for  some  muscles 
along  the  edges  it  lies  directly  under  the  skin  and  the 
ridge  between  the  manubrium  and  the  gladiolus  can  be 
felt  in  the  living,  a  fact  which  assists  in  determining  the 
position  of  the  different  ribs  in  cases  of  fracture,  as  the 
second  rib  articulates  at  this  point. 


FIG.  37.— A  and  B,  typical  ribs;  C,  first  rib;  D,  twelfth  rib.     1,  head;  2,  neck; 
3,  tuberosity;  4,  grooved  edge;  5,  shaft;  6,  oval  depression  for  costa  cartilage. 

The  Ribs. — The  ribs  are  twenty-four  in  number, 
twelve  on  each  side,  of  which  the  upper  seven,  which 
articulate  with  the  sternum  by  individual  cartilages,  are 
called  true  ribs,  the  other  five  false  ribs.  Of  the  false  ribs 
the  upper  three  articulate  indirectly  with  the  sternum 
through  the  seventh  cartilage,  with  which  their  cartilages 
unite,  while  the  other  two  have  their  anterior  extremities 
free  and  are  called  floating  ribs.  All  the  ribs  slope  down 
7 


98  THE    CHEST. 

toward  the  front  and  are  by  nature  more  freely  movable 
in  women  than  in  men.  Most  of  the  ribs  have  a  head 
divided  by  a  little  ridge  into  two  facets  for  articulation 
with  the  dorsal  vertebrae,  a  flattened  neck,  a  tuberosity  at 
the  base  of  the  neck  with  a  facet  for  articulation  with  the 
transverse  process  of  the  vertebra  below,  an  angle,  and 
a  shaft,  which  is  externally  convex  and  is  grooved  on  its 
lower  edge  for  the  intercostal  vessels  and  nerve.  The 
first  and  second,  eleventh  and  twelfth  ribs,  however,  are 
somewhat  peculiar,  the  first  two  being  shorter,  flatter 
and  rather  broader  than  the  rest  and  the  first  having  only 
one  facet  on  the  head,  while  the  last  two  have  only  one 
facet  on  the  head  and  no  neck  or  tuberosity. 

The  costal  cartilages  serve  to  prolong  the  ribs  and 
greatly  increase  the  elasticity  of  the  chest  wall.  They 
grow  longer  down  to  the  seventh  and  then  decrease  again 
in  length. 

The  ribs,  except  the  first  and  second,  which  are  pro- 
tected by  the  clavicle,  are  frequently  broken.  Such  a 
break  causes  pain  in  breathing  and  sometimes  the  end  of 
a  rib  pierces  the  lung  tissue  and  swelling  all  over  the 
body  results,  due  to  the  presence  of  air.  Caries  or  death 
of  the  rib  is  also  frequent.  Fracture  of  the  sternum  occurs 
occasionally,  generally  from  direct  force,  as  from  a  blow 
with  the  knee  in  foot-ball,  and  there  may  be  dislocation 
between  the  manubrium  and  gladiolus. 

Muscles  of  the  Chest. — The  spaces  between  the  ribs, 
from  the  tubercle  of  the  rib  behind  to  the  cartilage  in 
front,  are  filled  by  the  external  intercostal  muscles,  which 
pass  downward  and  forward  from  the  lower  border  of 
one  rib  to  the  upper  border  of  the  one  below.  There 
are,  therefore,  eleven  pairs  of  these  muscles.  There  are 
also  eleven  pairs  of  the  internal  intercostals ,  which  com- 
mence at  the  sternum  and  extend  back  to  the  angle  of 
the  rib.  These  extend  downward  and  backward.  The 
external  intercostals  raise  and  evert  the  ribs  in  inspira- 
tion, the  internal  depress  and  invert  them  in  expiration. 

The  chief    respiratory  muscle,    however,   is  the  dia- 


THE    CHEST.  99 

phragm,  a  somewhat  fan-shaped  muscle  that  forms  the 
floor  of  the  chest  cavity.  It  takes  its  origin  from  the 
ensiform  cartilage,  the  six  or  seven  lower  ribs  and  their 
cartilages,  and  from  the  upper  three  or  four  lumbar 
vertebrae,  that  is,  from  the  whole  of  the  internal  circum- 
ference of  the  thorax,  and  is  inserted  into  the  central 
cordiform  tendon.  It  has  several  large  and  several 
small  openings  for  the  aorta,  the  esophagus,  the  venae 
cavse,  the  thoracic  duct,  and  various  nerves,  and  its 


FIG.  38. — Interior  view  of  the  diaphragm.  (Leidy.)  1-3,  The  three  lobes 
of  the  central  tendon,  surrounded  by  the  fleshy  fasciculi  derived  from  the  inferior 
margin  of  the  thorax;  4,  5,  the  crura;  6,  7,  the  arcuate  ligaments;  8,  aortic  orifice; 
9,  esophageal  orifice;  10,  quadrate  foramen;  11,  psoas  muscle;  12,  quadrate 
lumbar  muscle. 

surfaces  are  covered  by  serous  membranes,  by  the  two 
pleurae  and  the  pericardium  above  and  by  the  peritoneum 
below.  It  partially  supports  the  heart  and  lungs.  Con- 
vex toward  the  chest,  it  becomes  flattened  in  contraction 
and  so  increases  the  capacity  of  the  chest.  It  aids  in  all 
expulsive  acts,  as  sneezing,  coughing,  laughing,  urinat- 
ing, defecating,  vomiting,  and  childbirth.  Hiccough  is 
spasm  of  the  diaphragm. 

The  arteries  of  the  chest  are  the  intercostal  branches 


100  THE    CHEST. 

of  the  subclavian  and  the  thoracic  aorta,  the  phrenic, 
mediastinal,  and  intercostal  branches  of  the  internal 
mammary,  and  the  thoracic  branches  of  the  axillary. 

The  nerves  are  the  intercostals  and  phrenics. 

Mammary  Glands. — On  the  outside  of  the  chest  walls, 
lodged  in  the  fascia  of  the  pectoral  muscles,  are  the 
mammary  glands,  accessory  organs  of  the  generative 
system.  They  exist  in  both  sexes  but  are  only  rudimen- 
tary in  the  male.  In  the  female  they  are  small  before 
puberty  but  enlarge  as  the  generative  organs  become 
more  completely  developed,  forming  two  hemispherical 
eminences,  one  on  either  side,  between  the  third  and 
seventh  ribs.  During  pregnancy  they  increase  once  more 
in  size  preparatory  to  the  secretion  of  the  milk,  and  in 
old  age  they  atrophy.  From  the  middle  projects  a  small 
pinkish-brown  conical  eminence,  the  nipple,  surrounded 
by  a  paler  area,  the  areola.  After  the  second  month  of 
pregnancy  both  nipple  and  areola  become  darker  in  color, 
a  point  of  great  diagnostic  value  in  early  pregnancy. 

The  mammary  glands  themselves  consist  of  lobules  of 
gland  tissue  with  a  central  lactiferous  tubule,  the  lobules 
being  gathered  into  lobes  with  fatty  tissue  between. 
From  the  juncture  of  these  tubules  result  fifteen  or 
twenty  excretory  ducts,  the  tubuli  lactiferi,  which  con- 
verge toward  the  areola.  Beneath  the  nipple  they  dilate, 
forming  the  ampullce,  and  then  contract  again  to  pass  out 
through  the  nipple  as  straight  tubes. 

Breast  abscess  occurs  most  commonly  in  nursing 
mothers,  as  where  a  part  is  most  active  there  is  most  dan- 
ger of  abscess.  Many  benign  tumors  of  the  breast,  as  the 
fibrous  tumors,  occur  and  are  especially  common  in 
young  women.  If  a  fibrous  tumor  is  allowed  to  develop 
it  may  become  cancerous.  Cancer,  however,  generally 
occurs  after  the  age  of  forty  and  is  usually  due  to  some 
irritation,  as  to  a  blow  from  a  ball. 

The  arteries  of  the  breasts  are  the  thoracic  branches  of 
the  axillary,  the  intercostal,  and  the  internal  mammary. 

The  nerves  are  from  the  thoracic  cutaneous. 


CHAPTER  VIII. 
THE  HEART  AND  CIRCULATION. 

The  Heart. — Shielded  within  the  chest  are,  as  has  been 
said,  the  heart  and  lungs.  The  heart  lies  on  the  left  side 
behind  the  sternum  and  the  cartilages  of  the  fourth  to 
seventh  ribs  in  a  closed,  conical,  membranous  sac,  the 


FIG.  39.— The  heart.     (Stoney.) 

pericardium,  which  is  attached  by  its  base  to  the  central 
tendon  of  the  diaphragm,  and  whose  point  extends  up 
between  the  pleurae  of  the  lungs.  This  sac  has  an  exter- 
nal fibrous  layer  and  an  internal  serous  layer  that  is  re- 
flected back  over  the  heart  itself,  forming  a  closed  sac, 

101 


TH-3    HP  ART.  .AND    CIRCULATION. 


within  which  a  thin  fluid  is  secreted  that  serves  to  reduce 
friction  during  the  movements  of  the  heart,  the  two  inner 
surfaces  sliding  over  each  other  with  every  beat. 

The  heart  itself  is  a  hollow  conical  organ  composed  of 
cardiac  muscle,  a  combination  of  smooth  and  striated 
fibers  found  nowhere  else  in  the  body.  It  lies  obliquely, 


FIG.  40.— Left  auricle  and  ventricle,  opened  and  part  of  their  walls  removed 
to  show  their  cavities:  1,  Right  pulmonary  vein  cut  short;  1',  cavity  of  left  auricle; 
3,  3',  thick  wall  of  left  ventricle;  4,  portion  of  same  with  papillary  muscle 
attached;  5,  the  other  papillary  muscles;  6.  6',  the  segments  of  the  mitral  valve; 
7,  in  aorta  is  placed  over  the  semilunar  valves;  8,  pulmonary  artery;  10,  aorta 
and  its  branches.  (Allen  Thomson.) 

base  up,  between  the  lungs,  suspended  by  the  great  blood- 
vessels and  with  the  apex  directed  downward,  forward, 
and  to  the  left,  the  apex  beat  being  normally  felt  in  the 
fifth  intercostal  space,  one  inch  inside  and  two  inches 
below  the  left  nipple.  In  size  it  varies  in  different  peo- 
ple and  is  generally  smaller  in  women  than  in  men.  On 
the  average  it  is  five  inches  long,  three  and  a  half 


THE    HEART    AND    CIRCULATION.  103 

inches  broad,  and  two  inches  thick.  A  man's  heart 
usually  weighs  about  eleven  ounces  and  that  of  a  woman 
nine  ounces.  It  never  leaks  except  from  disease  and 
such  leakage  is  fatal. 

The  Cavities. — The  heart  contains  four  cavities,  two 
auricles  above  and  two  ventricles  below,  with  a  longi- 
tudinal septum  between  the  auricle  and  ventricle  on  the 
right  and  those  on  the  left.  The  posterior  surface  is 
largely  made  up  of  the  left  ventricle  and  the  anterior  of 
the  right  ventricle.  The  right  auricle,  which  receives 
the  blood  from  the  general  circulation,  has  a  capacity 
of  about  two  fluid  ounces  and  is  larger  than  the  left, 
which  receives  the  blood  returning  from  the  lungs, 
though  its  walls  are  thinner.  Of  the  ventricles  the  left 


IVJ. 

lV3         \ 

RAV 

FIG.  41. — Orifices  of  the  heart,  seen  from  above,  both  the  auricles  and  the 
great  vessels  being  removed:  PA,  Pulmonary  artery  and  its  semilunar  valves; 
Ao,  aorta  and  its  valves;  RAV,  tricuspid,  and  LAV,  bicuspid  valves;  mv,  seg- 
ments of  mitral  valve;  Iv,  segment  of  tricuspid  valve.  (Huxley.) 

is  the  larger  and  its  walls  are  about  three  times  as  thick 
as  those  of  the  right,  for  it  has  to  send  the  blood  all  over 
the  body.  All  the  cavities  are  lined  with  smooth,  trans- 
parent, serous  membrane,  the  endocardium,  which  is  con- 
tinuous with  the  intima  of  the  great  vessels. 

The  Valves. — The  opening  from  the  auricle  into  the 
ventricle  on  either  side  is  guarded  on  the  ventral  side  by 
a  valve  formed  of  folds  of  endocardium.  The  valve  on 
the  right  side  has  three  flaps  or  cusps  and  is  called  the 


104  THE    HEART    AND    CIRCULATION. 

tricuspid  valve,  while  that  on  the  left  has  two  flaps,  larger 
and  thicker  than  those  of  the  tricuspid,  and  is  known  as 
the  bicuspid  or  mitral  valve.  The  flaps  of  either  valve  are 
kept  from  being  forced  into  the  auricle  in  closing  by  fine 
tendinous  cords,  the  chordce  tendinece,  which  are  attached 
to  the  columnce  carnece,  muscular  bands  or  columns  pro- 
jecting from  the  walls  of  the  ventricle,  which  contract 
and  hold  the  chordae  tendineae  taut.  The  opening  into 
the  pulmonary  artery  is  from  the  posterior  part  of  the 
right  ventricle  and  is  guarded  by  the  semilunar  or  pulmo- 
nary valve,  while  the  aortic  opening  from  the  left  ventricle 
is  guarded  by  a  similar  valve,  the  aortic  valve,  the  most 
important  valve  in  the  body.  All  these  valves  are  planned 
primarily  to  prevent  regurgitation  of  the  blood  during 
contraction  of  the  heart  muscle.  Pressure  in  the  ven- 
tricle must  exceed  that  in  the  arteries  before  the  semi- 
lunar  valves  will  open  and  the  blood  can  be  driven  out, 
just  as  the  auriculo-ventricular  valves  remain  closed  until 
the  pressure  in  the  auricles  exceeds  that  in  the 
ventricles. 

The  heart  beat  is  caused  by  the  twisting  of  the  heart 
upon  its  axis  during  contraction  of  the  muscle.  Nor- 
mally it  beats  rhythmically  and  regularly,  whatever  a 
person  does,  at  a  rate  of  about  seventy-two  contractions 
to  the  minute  in  the  adult.  To  the  regular  cardiac  cycle, 
as  it  is  called,  there  are  two  periods,  the  systole  and  the 
diastole,  the  former  representing  the  period  of  contraction 
of  the  ventricles,  when  the  blood  is  sent  to  the  lungs  and 
over  the  body,  and  the  latter  representing  the  period  of 
rest  following  the  emptying  of  the  ventricles,  during 
which  they  are  refilled.  Contraction  of  the  heart  occu- 
pies one-fifth  of  the  time  of  one  beat,  dilatation  two-fifths, 
and  the  pause  two-fifths.  There  are  really  two  systoles, 
one  of  the  auricles  and  one  of  the  ventricles,  but  they 
come  so  close  together  that  they  are  practically  simul- 
taneous so  far  as  sound  is  concerned,  though  they  can  be 
distinguished  by  sight.  During  systole  the  tricuspid 
and  mitral  valves  close  sharply  to  prevent  regurgitation 


THE    HEART    AND    CIRCULATION. 


105 


into  the  auricles,  while  the  semilunar  valves  open  to  let 
the  blood  out.  The  cardiac  cycle  is,  therefore,  as  follows: 
Circulation. — The  blood,  after  it  has  given  off  its  oxy- 
gen and  collected  carbon  dioxide,  returns  to  the  heart 
through  two  main  channels, the  superior  and  inferior  vence 
cavce,  the  former  bringing  the  blood  from  the  upper  part  of 


Pulmonary 
artery 


Superior 
vena  cava 

Right  auricle 
Inferior 
vena  cava 
Right 
ventricle 


Pulmonary 
capillaries 


-*  Left  ventricle 


Portal 
circulation 


Systemic 
capillaries 


FIG.  42. — Diagram  of  the  circulation.     (After  Kirke.) 

the  body,  including  the  head,  neck,  and  arms,  and  the  lat- 
ter from  the  lower  part  below  the  diaphragm.  The  two 
vessels  empty  along  with  the  coronary  sinus,  which  is 
guarded  by  the  coronary  valve,  into  the  right  auricle.  At 
the  same  time  that  they  empty  into  this  auricle  the  four 
pulmonary  veins,  the  only  veins  that  carry  arterial  or 
oxygenated  blood,  are  emptying  the  fresh  blood  from  the 
lungs  into  the  left  auricle.  When  both  auricles  are  full, 


106 


THE    HEART    AND    CIRCULATION. 


they  contract  and  send  the  blood  into  the  ventricles,  the 
auricular  systole.  As  the  blood  comes  through  into  the 
ventricles  it  probably  comes  around  by  the  walls  and 
closes  the  auriculo-ventricular  valves,  though  just  how 
the  valves  close  is  not  certain.  When  the  two  ventricles 
are  full  they  in  turn  contract,  the  ventricular  systole, 
and  the  blood  is  forced  out,  that  in  the  right  ventricle 
passing  to  the  lungs  for  its  new  supply  of  oxygen  through 
the  pulmonary  artery,  the  only  artery  to  carry  venous 
blood,  and  that  from  the  left  ventricle  entering  the  aorta 
for  general  distribution  through  the  body.  Following 
the  systole  is  a  pause,  the  diastole,  while  the  heart  fills 
again. 

Circulation  in  Fetus. — In  the  fetus  there  is  direct  com- 
munication between  the  two  auricles  through  the 
foramen  ovale,  which  normally 
closes  at  birth,  though  occa- 
sionally it  remains  open.  There 
is  also  communication  between 


arch  of  the  aorta  through  the 
ductus  arteriosus.  The  freshly 
oxidized  blood  comes  to  the 
fetus  through  the  placenta,  from 
which  it  is  brought  along  the 
umbilical  cord  in  the  umbilical 
vein  to  the  liver  and  thence  to 
the  inferior  vena  cava,  where  it 
mixes  with  the  blood  from  the 
lower  extremities.  By  the  in- 
ferior vena  cava  it  is  carried  to  the  right  auricle,  where 
the  Eustachian  valve — a  valve  between  the  inferior  vena 
cava  and  the  auriculo-ventricular  opening,  larger  in  the 
fetus  than  in  later  life  where  it  serves  no  special  purpose 
— guides  it  across  the  auricle  and  through  the  foramen 
ovale  to  the  left  auricle.  From  this  auricle,  together  with 
a  small  amount  of  blood  from  the  lungs,  it  goes  to  the  left 
ventricle  and  is  distributed  by  the  aorta  almost  entirely 


FIG.  43. — The  fetal  circulation. 


THE    HEART    AND    CIRCULATION.  107 

to  the  head  and  upper  extremities.  Hence  their  large  size 
and  perfect  development  at  birth.  Returned  from  the 
upper  extremities  by  the  superior  vena  cava,  the  blood 
enters  the  right  auricle  again  and,  passing  over  the 
Eustachian  valve  this  time,  descends  to  the  right  ven- 
tricle, from  which  the  greater  part  passes  by  the  pul- 
monary artery  and  the  ductus  arteriosus  to  the  descend- 
ing aorta,  though  a  small  amount  keeps  on  through  the 
pulmonary  artery  to  the  lungs.  In  the  aorta  it  mixes 
with  the  blood  from  the  left  ventricle  and  part  goes  to 
supply  the  lower  extremities,  though  the  greater  part  is 
carried  back  to  the  placenta  through  the  two  umbilical 
arteries.  The  fact  that  the  greater  part  of  the  blood 
traverses  the  liver  accounts  for  its  large  size  at  birth, 
while  the  lower  extremities,  which  receive  for  the  most 
part  blood  that  has  already  circulated  through  the  upper 
extremities,  are  of  small  size  and  imperfectly  developed. 

Arteries. — After  birth  the  arterial  blood  for  the  gen- 
eral circulation  leaves  the  heart  by  the  aorta,  the  main 
distributing  artery  of  the  body.  Through  this  and 
its  branches  it  is  carried  throughout  the  body  in  what, 
with  the  return  of  the  venous  blood  by  the  venae  cavae 
and  other  smaller  veins,  is  known  as  the  systemic  circula- 
tion. The  aorta  ascends  from  the  left  ventricle  and 
arches  backward  to  the  left  over  the  root  of  the  left 
lung  to  descend  along  the  spinal  column  at  the  left  to 
the  fourth  lumbar  vertebra,  about  opposite  the  umbilicus, 
where,  considerably  diminished  in  size  by  the  branches 
it  has  given  off,  it  divides  into  the  two  common  iliacs. 
For  convenience  its  different  parts  are  named,  according 
to  their  position,  the  ascending  aorta,  the  arch  of  the 
aorta,  and  the  descending  aorta,  the  last  being  subdivided 
into  the  thoracic  and  the  abdominal  aorta. 

From  the  ascending  aorta  come  off  the  coronary 
arteries  which  supply  the  heart  muscle  itself,  as  the  cor- 
onary sinuses  carry  off  the  venous  blood  from  the 
heart.  .  From  the  arch  are  given  off  the  left  common 
carotid  and  left  subclavian  and  the  innominate,  which 


108 


THE    HEART    AND    CIRCULATION. 


divides  into  the  right  common  carotid  and  right  sub- 
clavian. 

The  common  carotids  pass  up  the  neck  behind  the 
sterno-cleido-mastoid  muscles  in  a  line  from  the  sterno- 
clavicular  joint  to  a  point  mid- 
way between  the  mastoid  process 
and  the  angle  of  the  lower  jaw 
and  divide  opposite  the  upper 
border  of  the  thyroid  cartilage 
into  the  internal  and  external 
carotids,  of  which  the  former  with 
its  branches  supplies  the  anterior 
part  of  the  brain,  the  eye  and 
forehead,  and  the  latter  the  neck 
and  face. 

The  subclavian  is  the  artery  of 
the  upper  extremity  but  its 
vertebral  branch  goes  to  the 
brain,  where  with  its  fellow  it 
forms  the  basilar  artery,  whose 
branches  together  with  the 
branches  of  the  internal  carotid 
form  the  circle  of  Willis  at  the 
base  of  the  brain.  Other  branches 
of  the  subclavian  are  the  thyroid 
axis,  with  branches  to  the  neck 
and  shoulders;  the  internal  mam- 
mary, with  branches  to  the  chest 
walls,  mediastinum,  and  dia- 
phragm, such  as  the  musculo- 
phrenic  and  superior  epigastric; 
and  the  superior  intercostal.  At 
FIG.  44.— The  aortjB  and  their  the  lower  border  of  the  first  rib, 
over  which  it  passes,  the  name 

axillary  is  substituted  for  subclavian,  while  at  the  lower 
border  of  the  axilla,  where  it  starts  down  the  arm,  it 
is  called  the  brachial  artery.  At  the  elbow  the  brachial 
divides  into  the  radial  and  ulnar  arteries.  The  axillary 


THE    HEART    AND    CIRCULATION.  109 

artery  sends  branches  to  the  chest  and  shoulder  and  is 
more  frequently  injured  than  any  other  artery  except 
the  popliteal.  Aneurism  may  occur  in  it  and  is  very 
likely  to  occur  in  the  thoracic  aorta. 

From  the  thoracic  aorta  branches  go  to  various  of  the 
chest  contents,  while  the  abdominal  aorta  supplies  the 
abdominal  viscera.  Among  the  branches  of  the  abdomi- 
nal aorta  are:  the  celiac  axis,  which  has  a  gastric,  an 
hepatic,  and  a  splenic  branch;  the  superior  and  inferior 
mesenteric  to  the  intestines;  the  renal;  the  suprarenal; 
the  spermatic  or  ovarian;  the  inferior  phrenic;  and  the 
lumbar. 

The  common  iliacs  divide  at  the  upper  edge  of  the  sa- 
crum into  the  external  and  internal  iliacs,  of  which  the 
latter  with  its  branches  supplies  the  walls  and  viscera  of 
the  pelvis  and  the  inner  part  of  the  thigh.  The  external 
iliac  and  its  branches  go  to  the  thigh,  leg,  and  foot. 

Veins. — Of  the  veins  few  need  be  mentioned  by  name. 
The  deep  veins  have  the  same  names  as  the  arteries  they 
accompany,  though  there  are  two  innominate  veins  where 
there  is  only  one  innominate  artery,  the  subclavian  and 
internal  jugular  veins  on  either  side  joining  to  form  an  in- 
nominate vein  and  the  two  innominates  in  turn  forming 
the  superior  vena  cava.  Of  the  superficial  veins  the 
external  and  internal  jugular  correspond  to  the  common 
carotid  arteries  and  return  the  blood  from  the  head  and 
face.  The  external  jugular  vein  is  important  because  it 
is  the  largest  superficial  vein  in  the  neck  and  is  often  cut 
in  suicide.  The  median  vein  is  found  at  the  bend  of  the 
elbow  and  is  used  in  letting  blood  and  in  giving  salt 
solution,  while  the  basilic  is  on  the  inner  side  and  the 
median  cephalic  on  the  outer  side  of  the  upper  arm. 
Varicosity  often  occurs  in  the  internal  or  long  saphenous 
.  and  the  external  or  short  saphenous  in  the  leg.  The  in- 
ferior vena  cava  is  formed  by  the  juncture  of  the  two 
common  iliac  veins. 

Portal  Circulation. — The  portal  system  of  veins  includes 
four  large  trunks  which  collect  the  blood  from  the  viscera 


110  THE    HEART    AND    CIRCULATION. 

of  digestion,  the  superior  and  inferior  mesenteric  veins 
from  the  intestines,  the  splenic  vein  from  the  spleen,  and 
the  gastric  from  the  stomach.  These  join  together  to 
form  the  portal  vein,  the  only  vein  that  breaks  up  into 
capillaries.  This  divides  and  ramifies  through  the  liver, 
whence  it  emerges  as  the  hepatic  veins.  The  whole  is 
known  as  the  portal  circulation. 

Pulmonary  Circulation. — Of  the  pulmonary  circulation 
and  its  vessels  a  few  words  might  also  be  said.  The  pul- 
monary artery,  which  carries  the  blood  from  the  right 
ventricle  to  the  lungs,  is  only  about  two  inches  long  and 
divides  into  a  right  and  a  left  pulmonary  artery,  which 
pierce  the  pericardium  and  go  to  their  respective  lungs. 
The  right  one  is  the  larger  and  longer,  for  it  has  farther  to 
go  and  gives  off  a  branch  to  supply  the  third  lobe  of  the 
right  lung.  The  vessels  finally  divide  and  subdivide, 
terminating  in  the  pulmonary  capillaries.  The  venous 
capillaries  then  gather  together  to  form  a  main  vein  in 
each  lobule,  these  veins  uniting  into  two  trunks  for  each 
lung,  the  pulmonary  veins,  which  empty  into  the  left 
auricle. 

Nerves  of  Heart. — The  muscular  fibers  of  the  heart 
have  the  power  of  rhythmical  contraction.  Independent 
nerve  centers  or  ganglia  are  also  found  in  the  muscular 
walls  and  influence  the  mechanism  of  the  heart,  especi- 
ally the  acceleratory  mechanism.  Thus,  in  some  of  the 
lower  animals  the  heart  can  be  removed  from  the  body, 
and  if  placed  in  normal  salt  solution  will  go  on  beating 
for  some  time.  The  heart  is  controlled,  however,  by  two 
nerves,  the  vagus  or  pneumogastric  and  the  sympathetic. 
Of  these  the  vagus  is  the  inhibitory  mechanism.  It  acts 
as  a  check  and  makes  the  heart's  action  regular  and 
rhythmic.  If  it  is  cut,  the  action  of  the  heart  becomes  very 
rapid  and  irregular.  The  sympathetic  is  the  acceleratory 
mechanism.  When  the  vagus  alone  is  stimulated,  it 
first  slows,  then  stops  the  heart,  for  it  weakens  the  systole 
and  prolongs  diastole.  Acceleration  follows  stimulation 
of  the  sympathetic,  both  the  rapidity  and  the  force  of  the 


THE    HEART    AND    CIRCULATION.  Ill 

beat  being  increased.  When  a  person  faints  from  a  blow 
in  the  abdomen,  it  is  because  the  pneumogastric  is 
affected  and  inhibits  the  action  of  the  heart.  The  work 
of  the  heart  is  very  dependent  upon  its  nervous  condition 
and  functional  diseases  of  the  heart  are  practically  wholly 
due  to  nervous  derangement. 

Heart  Sounds. — Through  the  stethoscope  two  heart 
sounds  may  be  heard.  They  are  known  as  the  first  and 
second  sounds.  The  first  is  a  soft,  rushing  sound,  stronger 
and  louder  than  the  other,  and  is  caused  in  part  by  the 
contraction  of  the  muscle  itself  when  the  blood  is  forced 
out  and  in  part  by  the  closure  of  the  auriculo-ventricular 
valves.  The  second  sound  is  shorter  and  sharper,  a  snap, 
and  is  caused  by  the  closure  of  the  semilunar  valves 
when  the  contraction  of  the  ventricles  ceases  and  they 
begin  to  refill.  In  certain  diseased  conditions,  where 
the  edges  of  the  valves  are  roughened,  they  do  not  snap 
properly  and  the  sound  varies  from  the  normal. 

The  Heart  Beat. — The  rate  of  the  heart  beat  is  propor- 
tionate to  the  size  of  the  person  and  increases  in  rapidity 
as  the  size  diminishes.  If  the  ear  is  placed  over  the  abdo- 
men of  a  pregnant  woman,  the  heart  of  the  fetus  can  be 
heard  beating  very  rapidly.  In  prolonged  labor  it  may 
become  more  rapid  or  very  faint  and  warn  the  doctor 
that  something  should  be  clone.  The  usual  rate  of  the 
pulse  in  the  fetus  is  140  to  150  times  a  minute,  though  it 
varies  with  size  and  sex.  At  birth  it  drops  to  140  to  130; 
for  the  first  year  it  is  130  to  115;  for  the  second  year  115 
to  105;  for  the  third  year  105  to  95;  from  the  seventh  to 
the  fourteenth  years  80  to  90;  from  the  fourteenth  to  the 
twenty-first  years  75  to  80;  from  twenty-one  to  sixty  60 
to  75.  In  old  age  it  rises  a  little  and  is  75  to  80.  The  rate 
is  higher  in  the  average  woman  than  in  the  average  man 
and  increases  with  exercise,  with  increase  of  temperature, 
and  in  high  altitudes,  where  the  atmospheric  pressure  is 
less. 

At  each  beat  of  the  heart  from  four  to  six  ounces  of 
blood  are  expelled  into  the  plumonary  artery  and  the 


112  THE    HEART    AND    CIRCULATION. 

aorta,  and  in  22  or  23  beats  all  the  blood  in  the  body 
passes  through  the  heart.  The  power  exerted  by  the 
heart  every  minute  in  thus  driving  the  blood  upon  its 
course  has  been  estimated  as  sufficient  to  raise  its  own 
weight,  three-quarters  of  a  pound,  the  height  of  the 
Washington  monument  or  150  meters;  for  the  ventricles 
have  to  force  the  blood  into  vessels  already  full. 

Factors  Affecting  Circulation. — There  are  three  main 
factors  in  the  circulation:  1.  the  systole,  which  gives  the 
blood  its  first  impulse;  2.  the  peripheral  resistance  in  the 
capillaries,  which  serves  to  hold  it  in  check,  slowing  the 
circulation  and  doing  away  with  its  rhythmic  character, 
and  3.  the  elasticity  of  the  walls  of  the  arteries. 

If  a  ligature  is  tied  about  an  artery,  there  is  a  swelling 
on  the  side  toward  the  heart,  while  in  the  case  of  a  vein, 
the  swelling  is  on  the  side  away  from  the  heart,  that  is, 
the  swelling  is  in  either  case  on  the  side  from  which  the 
blood  comes.  When  an  artery  is  cut,  however,  the  blood 
comes  out  rhythmically  in  spurts,  though  from  a  cut  vein 
it  oozes  slowly  and  regularly.  For  the  blood  is  pumped 
out  by  the  heart  rhythmically  and  its  rhythmic  beating 
against  the  walls  of  the  artery  is  felt  in  the  pulse,  which 
follows  slightly  after  the  beat  of  the  heart  itself.  The 
pulse  is  due  to  the  fact  that  the  vessels  into  which  the 
blood  is  forced  are  already  full.  This  causes  a  local 
dilation  at  the  beginning  of  the  artery  which  passes  with 
diminishing  force  along  its  entire  length,  the  distention 
being  due  to  the  fact  that  more  force  is  needed  to  drive 
the  blood  through  the  small  arteries  and  capillaries 
than  to  stretch  the  elastic  walls  of  the  aorta  and  the  large 
arteries.  It  is  this  elastic  character  of  the  arteries  that 
makes  the  blood  flow  constant,  for  otherwise  the  blood 
would  come  intermittently  in  jets,  as  it  is  pumped  from 
the  heart.  The  elastic  walls  of  the  vessels,  however, 
offer  a  certain  resistance  to  the  pumping  of  the  fluid 
through  them  and  at  the  same  time,  by  relaxing  between 
whiles,  allow  a  certain  amount  of  fluid  to  be  retained  in 
them,  so  that  they  continue  full  and  the  flow  is  more  or 


THE    HEART    AND    CIRCULATION.  113 

less  constant.     The  insufficient  outlet  also  helps  to  make 
the  flow  constant. 

By  the  time  the  blood  reaches  the  veins  its  rhythmic 
character  has  been  done  away  with,  but  though  there  are 
no  elastic  walls  in  the  veins,  it  still  has  force  enough  after 
the  slowing  in  the  capillaries  to  return  to  the  heart. 
In  this  it  is  aided  to  a  certain  extent  by  the  valves  and 
by  the  action  of  the  skeletal  muscles  as  they  contract  and 
expand,  especially  in  the  arms  and  legs,  where  the  blood 
runs  perpendicularly  and  there  is  a  high  column  to  be 
supported  There  are  also  more  veins  than  arteries,  each 
large  artery  having  two  large  veins,  the  venae  comites,  to 
help  get  the  blood  back  to  the  heart,  and  the  veins  anas- 
tomose freely.  Thus,  if  the  blood  cannot  get  back  by  one 
channel  it  does  by  another.  In  parts  like  the  brain,  where 
it  is  very  important  that  there  should  be  no  compression, 
since  any  disturbance  of  circulation  would  lead  to  serious 
results,  the  vessels  are  enclosed  in  thick  walls,  and  in  the 
liver,  through  which  all  the  blood  passes  and  where  com- 
pression is  sure  to  cause  trouble,  the  veins  are  simply 
caverns  carved  out  in  the  organ  and  have  no  walls. 
They  lie  open  when  the  organ  is  opened.  Varicose 
veins  are  the  result  of  valves  giving  way  through  inherited 
weakness  or  disease  so  that  others  have  an  unduly  large 
weight  to  support. 

The  Pulse. — The  pulse  wave  is  characterized  by  a 
quick  rise  and  a  slow  fall,  though  this  cannot  ordinarily 
be  distinguished  by  the  finger.  In  some  slow  fevers,  how- 
ever, the  fall  is  very  long  and  distinct  ripples  can  be  felt. 
This  is  known  as  the  dicrotic  pulse.  With  age  the 
arterial  walls  grow  stiffer  and  more  rigid  and  less  adapted 
to  their  work.  In  certain  cases  of  heart  disease  the  heart 
does  not  transmit  all  the  beats  to  the  pulse  and  to  get  the 
true  rate  the  heart  must  be  listened  to. 

The  rate  at  which  the  pulse  wave  travels  varies  with 
the  size  of  the  artery  and  the  force  of  the  heart  beat 
but  is  about  15  to  20  feet  a  second.  The  flow  is  most 
rapid  in  the  arteries  because  they  are  nearest  the  heart, 

8 


114  THE    HEART    AND    CIRCULATION. 

where  the  pressure  is  greatest,  and  slowest  in  the  capil- 
laries, where  the  area  is  greatest,  the  sectional  area  of 
the  capillaries,  known  as  the  peripheral  area  because  it 
is  farthest  from  the  heart,  being  larger  than  that  of  the 
large  arteries.  Thus  rapidity  of  flow  varies  with  pres- 
sure and  with  area. 

Blood  Pressure. — Liquids,  moreover,  are  incompres- 
sible and  exert  pressure  on  the  walls  of  the  tubes  through 
which  they  pass.  The  amount  of  pressure  depends 
upon  the  inflow  and  outflow,  increasing  directly  with  the 
inflow  and  inversely  with  the  outflow,  that  is,  the  smaller 
the  outlet  the  greater  the  pressure,  and  vice  versa.  The 
pressure  is  also  greatest  nearest  to  the  inflow  and  grad- 
ually decreases  with  distance  until  at  the  point  of  out- 
flow there  is  practically  no  pressure.  So,  in  the  arteries 
the  blood  pressure  is  greatest  in  the  large  vessels  nearer 
the  heart  and  gradually  decreases  as  they  branch  into 
smaller  and  smaller  vessels.  In  passing  through  the 
capillaries,  owing  to  their  small  size  and  resultant  in- 
creased friction,  the  blood  meets  with  more  resistance, 
the  peripheral  resistance,  and  this  resistance  usually 
regulates  the  pressure  in  the  arteries.  The  greater 
the  peripheral  resistance,  as  a  rule,  the  greater  the  ar- 
terial pressure.  The  pressure  in  the  capillaries  is  very 
slight  and  in  the  veins  there  is  practically  no  pressure. 
In  fact,  in  the  large  veins  near  the  heart  the  pressure 
is  negative  and  the  blood  is  almost  sucked  into  the 
heart. 

Pressure,  then,  is  greatest  in  the  arteries  and  least  in 
the  veins,  while  the  rate  of  flow  is  fastest  in  the  arteries 
— 300  to  500  millimeters  a  second — and  slowest  in  the 
capillaries — 75  millimeters  a  second — being  a  little 
faster  again  in  the  veins — 200  millimeters  a  second. 

Blood  pressure  is  gauged  by  opening  a  vessel  and  in- 
serting a  manometer,  the  pressure  being  determined 
by  the  height  to  which  the  mercury  is  raised.  In  man 
the  pressure  in  the  arteries  is  120  to  160  millimeters. 
It  is  considerably  heightened  during  inspiration  by 


THE    HEART    AND    CIRCULATION.  115 

the  increased  pressure  of  the  lungs  on  the  heart  and 
great  vessels.  In  pericarditis  the  opposite  is  true. 

When  the  blood  pressure  is  high,  the  pulse  is  small  and 
travels  fast,  because  the  wall  of  the  artery  is  already 
highly  stretched.  Such  a  pulse  is  hard  and  incompress- 
ible. A  large  pulse  occurs  where  the  heart  is  strong 
and  the  pressure  is  low,  owing  to  peripheral  dilatation. 
A  low-pressure  pulse  is  soft  and  compressible  if  the 
heart  beat  is  weak.  A  slow  pulse  is  generally  stronger 
than  a  rapid  one. 

The  nerve  supply  of  the  blood-vessels  comes  from  the 
spinal  cord  through  the  vasomotor  nerves,  which  are 
connected  with  the  sympathetic  system  and  are  distrib- 
uted to  the  smooth  muscle  fibers  of  the  vessels.  They 
are  of  two  classes,  the  vasoconstrictors,  which  diminish 
the  lumen  of  the  vessels,  and  the  vasodilators,  which 
increase  the  size  of  the  vessels.  By  these  nerves  the 
general  tone  of  the  arteries  is  kept  up.  They  are  dis- 
tributed chiefly  to  vessels  in  the  skin  and  in  the  abdom- 
inal organs  and  the  constrictors  are  probably  the  more 
important.  When  the  constrictors  are  stimulated, 
three  phenomena  occur:  1.  diminished  flow  through 
the  vessel,  due  to  its  diminished  size;  2.  increased  gen- 
eral arterial  pressure,  and  3.  increased  flow  through 
the  other  arteries.  When  the  dilators  are  stimulated 
the  opposite  effect  is  produced:  1.  the  flow  through  the 
vessel  is  increased;  2.  there  is  decreased  arterial  pres- 
sure, and  3.  there  is  decreased  flow  through  the  other 
arteries.  The  palor  of  fright  is  due  to  the  action  of 
the  vasoconstrictor  nerves  of  the  face  and  blushing 
to  the  action  of  the  vasodilators.  Heat  stimulates 
the  vasodilators  so  that  more  blood  goes  to  the  skin, 
perspiration  begins,  and  the  body  is  cooled  by  evapo- 
ration. Cold  stimulates  the  vasoconstrictors  and  the 
blood  is  kept  within  the  body,  where  it  cannot  cool. 
If  a  part  has  too  much  blood,  an  impulse  passes  by 
the  vasoconstrictors  to  lessen  the  supply,  while  if 
more  blood  is  needed  a  message  goes  to  the  central  ner- 


116  THE    HEART    AND    CIRCULATION. 

vous  system  and  an  impulse  passes  by  the  vasodilators 
to  flush  the  organ.  The  more  active  a  part  is  in  func- 
tioning the  greater  the  number  of  capillaries,  except 
in  the  brain,  which  has  only  large  vessels.  The  vessels 
of  the  intestines  contain  much  blood  and  are  capable 
of  containing  all  the  blood  in  the  body. 

The  Blood. — The  blood  itself,  which  thus  circulates 
through  the  body,  carrying  nutrition  to  the  tissues  and 
removing  waste,  is  a  complex  fluid  of  a  bright  red  color. 
Its  amount  has  been  calculated  to  be  about  one-thir- 
teenth of  the  body  weight.  One-fourth  of  it  is  gener- 
ally in  the  heart,  lungs,  and  large  arteries  and  veins, 
one-fourth  in  the  liver,  one-fourth  in  the  skeletal  mus- 
cles, and  one-fourth  variously  distributed  through  the 
other  organs.  If  there  is  too  little  blood,  the  vital  pro- 
cesses cannot  go  on  as  they  should,  while  too  great  a 
supply  causes  weakness  rather  than  strength.  So  the 
tendency  is  to  keep  the  amount  constant  and  any  blood 
added  is  disposed  of  and  any  blood  lost  is  replaced.  In 
starvation  it  is  the  last  tissue  to  be  used  up,  for  on  it 
the  life  of  the  other  tissues  depends. 

Composition. — In  composition  the  blood  is  practi- 
cally the  same  in  all  arteries  and  fundamentally  the  same 
everywhere,  but  in  passing  through  certain  organs  cer- 
tain substances  are  added  to  or  taken  from  it,  so  that 
its  character  changes  more  or  less.  Thus  it  varies  some- 
what in  composition  in  different  parts  of  the  body,  as 
in  the  liver  and  kidneys.  It  has  five  main  functions: 
1.  the  conveying  of  fuel  from  the  digestive  tract  to  the 
tissues,  or  force  production;  2.  the  carrying  of  oxygen 
to  the  tissues;  3.  the  carrying  of  tissue-building  mate- 
rials, or  tissue  building;  4.  the  distribution  of  heat;  and 
5.  the  removal  of  waste  products. 

The  blood  is  slightly  alkaline  in  reaction,  of  a  saltish 
taste,  and  has  a  specific  gravity  of  1^55.  Its  temper- 
ature is  about  100°  Fahrenheit  or  37.8°  Centigrade.  It 
is  made  up  of  two  parts,  the  plasma  or  fluid  portion  and 
the  corpuscles  or  solid  portion.  The  plasma,  again, 


THE   HEART    AND   CIRCULATION.  117 

which  is  transparent  and  almost  colorless,  consists  of 
two  materials,  the  blood  serum  and  fibrin.  Fibrin  does 
not  exist  as  such  in  the  body  nor  in  freshly  shed  blood, 
but  there  is  a  substance  named  fibrinogen  which  is  worked 
on  by  another  substance,  the  fibrin  ferment,  to  form 
fibrin.  Both  fibrin  ferment  and  fibrinogen  can  be  iso- 
lated from  the  blood. 

Coagulability. — In  the  body  the  blood  is  perfectly 
fluid  and  under  normal  conditions  does  not  coagulate. 
But,  though  fluid  when  first  shed,  upon  standing  it 
gradually  becomes  viscid,  that  is,  in  two  or  three  minutes, 
then  jelly-like,  in  five  to  ten  minutes,  and  grows  firmer 
and  firmer  until  there  finally  appears  around  this  jelly- 
like  mass  or  clot  a  yellowish  fluid,  the  serum.  The 
clot  is  made  up  of  the  corpuscles  and  fibrin.  If  some 
blood  is  drawn  and  set  on  ice  until  the  corpuscles  settle, 
the  plasma  can  then  be  drawn  off,  and  after  it  has  stood 
awhile  in  a  warm  place  coagulation  will  take  place,  a  mass 
of  fibrin  forming  in  the  middle.  It  takes  from  one  to 
two  hours  for  clotting  to  be  complete.  In  very  slow 
clotting  at  a  low  temperature  the  white  corpuscles  ap- 
pear in  a  layer  on  top  of  the  clot,  the  buffy  coat. 

Of  fibrin  little  is  known,  but  its  formation  is  the 
most  important  step  in  clotting,  as  its  presence  is  ab- 
solutely essential.  If  it  is  removed  by  whipping,  the 
blood  will  not  clot.  It  is  a  delicate,  stringy  material, 
elastic  and  contractile,  and  contains  certain  salts  of  lime 
and  magnesium,  upon  whose  presence  its  power  of  coagu- 
lation depends.  The  coagulability  of  blood  differs  in 
different  people  and  is  occasionally  so  little  as  to  make 
operation  dangerous. 

The  most  favorable  temperature  for  clotting  is  that 
of  the  body,  extreme  heat  preventing  it  and  cold  delaying 
it.  That  the  blood  does  not  clot  in  the  body  must  be  due 
to  some  relation  between  the  blood  and  the  walls  of  the 
arteries  and  veins  that  prevents  it,  just  as  the  walls  of 
the  stomach  are  not  digested  by  the  juices  secreted. 
Though  coagulation  does  not  normally  take  place  in  the 


118  THE    HEART    AND    CIRCULATION. 

body,  it  does  take  place  when  a  blood-vessel  is  injured  or 
when  the  blood  comes  in  contact  with  the  air,  a  wise  pro- 
vision of  nature,  as  otherwise  the  tendency  would  be  for 
bleeding  to  go  on  indefinitely  after  injury.  The  greater 
the  surface  with  which  the  blood  comes  in  contact 
the  more  quickly  it  clots.  Injury  to  the  vessel  wall 
itself  is  necessary;  the  endothelium  must  be  cracked. 
Under  extreme  injury  the  muscular  coat  of  the  vessel 
undergoes  spasmodic  contraction  and  partially  closes 
it.  Hence  a  wound  caused  by  tearing  is  less  likely  to 
bleed  than  one  due  to  cutting. 

The  valves  of  the  heart,  which  are  covered  with  en- 
dothelium, are  frequently  the  seat  of  fibrin  coagulation, 
bits  of  the  fibrin  thus  formed  giving  rise  to  conditions 
in  various  kinds  of  heart  trouble.  Or  the  bits  of  fibrin 
float  in  the  blood  and  perhaps  lodge  in  the  small  ves- 
sels of  the  brain  and  cause  apoplexy.  Pus  in  various 
parts  of  the  body  will  set  up  coagulation  in  nearby 
arteries.  In  fact,  the  presence  of  any  foreign  sub- 
stance in  the  blood  causes  clotting. 


FIG.  45. — Cells  of   blood:    a,  Colored    blood-corpuscles  seen  on  the  flat;  6,  on 
edge;  c,  in  rouleau;  d,  blood  platelets.      (Leroy.) 

Blood-corpuscles. — The  solid  parts  of  the  blood  are  the 
red  corpuscles,  the  white  corpuscles,  and  the  blood  plaques 
or  plates.  It  is  to  the  red  corpuscles,  or  erythrocyles 
which  number  about  5,000,000  to  the  cubic  milli- 
meter of  blood,  that  the  color  of  the  blood  is  due. 
Under  the  microscope  they  appear  as  small,  spher- 
ical, biconcave  discs  with  a  slightly  greenish-yellow 


THE    HEART    AND    CIRCULATION.  119 

color,  which  have  a  tendency  to  form  in  rouleaux. 
They  are  homogeneous,  with  no  limiting  membrane, 
and  are  made  up  of  a  fine  network  of  tissue,  the  stroma, 
in  which  is  embedded  the  hemoglobin  or  coloring  mat- 
ter. This  hemoglobin  is  a  crystalline  body  and  the 
most  complex  substance  known  to  chemists.  The  cor- 
puscles are  very  flexible  and  can  squeeze  through  small 
apertures,  as  in  the  tiny  capillaries,  and  regain  their 
shape.  They  are  probably  formed  chiefly  in  the  red 
bone  marrow  at  the  ends  of  the  bones,  which  under  the 
microscope  shows  red  corpuscles  in  various  stages  of 
growth,  and  also  in  the  spleen,  for  which  no  other  use 
is  known.  Their  function  is  to  carry  oxygen,  which 
forms  a  chemical  combination,  though  an  extremely 
loose  one,  with  the  hemoglobin.  As  the  tissues  are 
more  greedy  of  oxygen  than  is  the  hemoglobin,  they 
rob  the  corpuscles  of  it. 


FIG.  46. — Various   forms   of  leucocytes:  a,  Small  lymphocyte;  6,  large  lympho- 
cyte; c,  polymorphonuclear  neutrophile;  d,  eosinophile.     (Leroy.) 

The  white  corpuscles  or  leucocytes  are  much  fewer  in 
number,  about  one  to  from  300  to  700  of  the  red,  the 
average  number  being  5,000  to  10,000  to  the  cubic  milli- 
meter. They  are  larger  than  the  red  corpuscles,  color- 
less, and  spherical  when  at  rest.  Their  structure  is  more 
definite,  there  .being  a  definite  cell  substance  or  proto- 
plasm and  one  or  more  nuclei,  which  vary  more  or  less 
in  shape  and  size.  The  corpuscles  are  classed  in  accord- 
ance with  these  variations  in  the  nuclei.  They  are 
most  numerous  during  digestion  and  are  probably  formed 
in  the  lymphatic  system,  constantly  passing  from  the 
lymphatics  to  the  arteries  and  veins.  For  they  have 


120  THE    HEART    AND    CIRCULATION. 

the  function  of  amoeboid  movement  by  which  they  not 
only  wander  from  place  to  place  in  the  blood,  keeping 
close  to  the  sides  of  the  vessels,  but  pass  through  the 
walls  of  the  capillaries,  probably  between  the  cells 
which  form  their  lining,  into  the  lymph  spaces.  This 
is  known  as  migration  of  the  white  corpuscles.  In  in- 
flammation they  collect  in  the  inflamed  area  to  assist 
in  allaying  the  inflammation  by  absorbing  and  carry- 
ing off  its  products.  Fof  they  carry  waste  products 
and  destroy  poisons,  acting  as  scaven^  rs  and  pro- 
tectors of  the  body.  When  they  are  unsuccessful  and 
the  inflammation  gets  the  better  of  them,  they  become 
pus  corpuscles. 

Besides  the  corpuscles  there  are  seen  floating  in  the 
blood  small  disk-like  substances  with  no  special  char- 
acteristics, the  blood  plaques  or  plates,  whose  function 
is  unknown. 

In  anemia  the  red  corpuscles  are  diminished  and  the 
white  corpuscles  and  blood  plaques  increased  in  number. 
After  excessive  bleeding  normal  salt  solution  is  in- 
jected, subcutaneously  or  by  rectum,  as  being  nearly 
equivalent  to  blood  serum  in  composition,  and  the  re- 
newal of  the  solid  elements  is  left  to  time.  The  length 
of  time  needed  for  their  restoration  is  about  a  week, 
except  in  the  case  of  the  hemoglobin,  which  takes 
longer. 


CHAPTER   IX. 
THE  LUNGS  AND  RESPIRATION. 

Besides  the  heart  and  the  great  vessels  the  chest 
contains  the  lungs,  the  chief  organ  of  respiration,  which, 
with  the  rest  of  the  respiratory  system,  will  now  be 
treated.  The  nose  and  mouth,  through  which  the  air 
first  enters  the  body,  have  already  been  spoken  of. 
From  them  the  air  passes  through  the  larynx  to  the 
trachea,  thence  to  the  bronchi,  and  so  to  the  lungs, 
where  the  supply  of  oxygen  for  the  tissues  is  taken  from 
the  air  by  the  hemoglobin,  of  the  blood. 

The  Larynx. — The  larynx  lies  in  front  of  the  pharynx 
at  the  upper  and  fore  part  of  the  neck,  where  it  causes 
a  considerable  projection,  k'lown  as  Adam's  apple. 
It  is  a  triangular  box,  base  up,  flattened  at  the  back, 
in  front,  and  at  the  sides,  but  becoming  cylindrical  be- 
low. Above  it  opens  into  the  bottom  of  the  pharynx 
and  below  into  the  trachea.  It  is  lined  with  mucous 
membrane.  Its  opening  at  the  base  of  the  tongue  is 
closed  during  swallowing  by  a  little  door-like  valve  of 
fibre-cartilage,  the  epiglottis,  to  pre ,  ent  the"  entrance 
of  food. 

Nine  cartilages  go  to  make  up  the  larynx,  of  which 
the  most  important  are  the  thyroid  and  cricoid  car- 
tilages and  the  epiglottis  already  mentioned.  The 
thyroid  is  the  largest  and  is  open  behind,  its  two  alae 
or  wings  meeting  in  an  acute  angle  in  front  and  forming 
the  Adam's  apple,  always  more  prominent  in  the  male 
than  in  the  female.  It  is  attached  above  to  the  hyoid 
bone  and  has  cornua  or  horns  on  either  side,  top  and 
bottom.  The  cricoid  or  ring-like  cartilage  resembles 
a  seal  ring  with  the  stone  placed  posteriorly.  It  is 
stronger  than  the  thyroid  and  forms  the  lower  part  of 

121 


122  THE    LUNGS    AND    RESPIRATION. 

the  cavity  of  the  larynx.  Inside  and  resting  on  the 
upper  border  of  the  cricoid  are  the  two  smaller  arytenoid 
or  pitcher-like  cartilages,  pyramidal  in  shape,  and  sur- 
mounting these  again  the  two  cornicula  laryngis.  The 
two  cuneiform  cartilages  are  in  the  free  borders  of  the 
folds  of  mucous  membrane  which  extend  from  the  apex 
of  the  arytenoids  to  the  sides  of  the  epiglottis.  Numer- 
ous small  muscles  serve  to  bind  these  various  cartilages 
together. 

At  the  angle  of  the  thyroid  cartilage  in  front  are  at- 
tached the  epiglottis  at  the  top  and  just  below  that  the 
superior  or  false  vocal  cords,  two  folds  of  mucous  mem- 
brane enclosing  the  superior  thyro-arytenoid  ligaments. 
Lower  still  are  found  the  inferior  or  true  vocal  cords, 
which  are  formed  by  the  inferior  thyro-arytenoid  lig- 
aments covered  with  a  thin,  tightly  fitting  mucous  mem- 
brane. Both  sets  of  vocal  cords  as  well  as  the  epiglot- 
tis may  be  seen  by  means  of  a  head  and  a  throat  mir- 
ror. Between  the  true  vocal  cords  is  a  narrow  tri- 
angular interval  called  the  glottis.  It  is  by  means  of  the 
vibrations  of  these  cords  that  sound  is  produced.  The 
false  vocal  cords  cannot  produce  sound,  though  they 
can  modify  it  indirectly.  Quality  of  voice,  as  treble, 
base,  etc.,  depends  upon  the  size  of  the  larynx  and  the 
length  and  elasticity  of  the  vocal  cords.  Modulation 
is  produced  by  changing  the  form  of  the  cavity  of  the 
mouth  and  nose.  In  whispering  the  lips  take  the 
place  of  the  vocal  cords  and  produce  sound  by  the 
vibration  of  their  muscular  walls. 

Instead  of  tracheotomy  laryngotomy  is  sometimes 
done  in  the  depression  between  the  thyroid  and  the 
cricoid,  which  may  be  felt  on  the  living.  Foreign  bodies 
sometimes  get  into  the  larynx  and  have  to  be  removed, 
or  the  mucous  membrane  may  become  inflamed,  caus- 
ing laryngitis.  Syphilis  attacks  the  larynx,  and  tuber- 
culosis  and  cancer  of  the  larynx  occur,  these  last  two 
being  generally  fatal.  Edema  of  the  glottis  may  also 
occur. 


THE    LUNGS    AND    RESPIRATION. 


123 


The  Trachea. — The  trachea  is  a  membranous  tube  ex- 
tending down  from  the  larynx  for  about  four  and  a 
half  inches  to  the  fourth  or  fifth  dorsal  vertebra,  where 
it  divides  into  the  right  and  left  bronchi.  It  is  formed 
of  sixteen  to  twenty  imperfect  cartilaginous  rings, 
open  behind,  enclosed  in  a  double  elastic  fibrous 


FIG.  47. — The  larynx,  trachea  and  bronchi.     (After  Sobotta.) 

membrane,  and  is  lined  with  ciliated  mucous  mem- 
brane. The  rings  are  for  strength  and  in  the  interval 
at  the  back  where  they  are  wanting  there  is  one  layer 
of  longitudinal  and  another  of  transverse  unstriped 
muscle  fibers.  The  passage  is  kept  clear  by  the  action 
of  the  cilia,  which  sweep  up  and  out  any  particles  of 
dust  that  become  entangled  in  the  mucus.  Trache- 
otomy is  generally  done  about  one  inch  below  the  cri- 


124 


THE    LUNGS    AND    RESPIRATION. 


coid,  just  above  the  sternal  notch,  incision  being  made 
through  the  cartilage. 

Extending  up  on  either  side  of  the  upper  trachea  in 
the  neck  are  the  two  lobes  of  the  thyroid  gland,  the 
isthmus,  which  connects  the  lobes,  covering  the  trachea 
below  anteriorly.  The  function  of  the  gland  is  ob- 
scure, but  it  has  an  internal  secretion  of  great  im- 
portance in  the  metabolic  processes.  Its  removal  or 


Thyreoict  cartilage 


Thyreoliyoiileus 
Right  common  carotid  artery 


Right  internal  jugular  vei, 


Scalentti  anterior 


Cricothyreoideus 


Fio.  48. — The  upper  thorax  of  a  child  eight  years  old,  'showing  the  thyroid  and 
thymus  glands.     (Sobotta.) 

disease  is  followed  by  general  disturbances  of  mind  and 
body.  The  injection  of  thyroid  extract  has  proved 
effective  as  treatment.  In  goiter  the  gland  becomes 
enlarged.  The  thymus  gland  lies  below  the  thyroid 
gland  at  birth,  in  front  of  and  at  the  sides  of  the  trachea, 
and  runs  down  behind  the  sternum.  It  is  largest  at 
the  end  of  the  second  year,  after  which  it  atrophies, 
being  almost  absent  at  puberty.  It,  too,  is  ductless  and 
its  function  is  not  well  understood. 


THE    LUNGS    AND    RESPIRATION. 


125 


The  Bronchi. — The  two  bronchi,  of  which  the  right  is 
the  larger  and  shorter,  resemble  the  trachea  in  struc- 
ture. As  they  enter  the  root  of  the  lung  they  divide, 
the  right  into  three  and  the  left  into  two  branches,  one 
for  each  lobe,  after  which  they  divide  and  subdivide, 
the  bronchioles  becoming  smaller  and  smaller  and  finally 
ending  in  the  infundibula,  pouch-like  places  lined  with 
air  cells,  in  which  cilia  keep  the  air  in  motion.  As  they 
grow  smaller  the  bronchioles  gradually  become  wholly 
membranous. 

The  Lungs. — The  lungs  themselves,  two  in  number, 
lie  each  in  a  serous  sac  or  pleura,  similar  in  structure 


Right  common 

carotid   artery. 

Subclavian 

arteries . 

Innominate 
artery. 

Arch  of  aorta 
Right  lung. 

Superior  vena 

cava. 
Right  auricle. 


Larynx. 


Trachea. 
Subclavian 
arteries. 


Pulmonary 
artery. 


FIG.   49. — Relation  of   lungs   to   other   thoracic   organs.     (Ingals.) 

to  the  pericardium  and  serving  a  like  purpose.  The 
outer  layer  of  the  pleura  is  reflected  back  over  the  tho- 
racic wall  and  'diaphragm.  There  is  no  pleural  cavity 
in  health  between  the  two  layers  of  the  pleura,  the  two 
surfaces  being  in  close  contact,  though  moistened  with 
lymph  to  prevent  friction  during  respiration.  In  in- 


126  THE    LUNGS    AND    RESPIRATION. 

flammation  of  the  pleurae  or  pleurisy,  they  become  thick- 
ened and  roughened  and  friction  results,  as  is  shown 
by  the  sounds  heard  through  the  stethoscope.  Fric- 
tion causes  effusion  and  fluid  collects.  This  generally 
absorbs  again,  but  occasionally  the  serous  fluid  becomes 
pustular  and  empyema  results. 

In  front,  between  the  two  pleurae,  which  are  wholly 
separate,  is  the  mediastinal  space  or  mediastinum,  which 
extends  from  the  sternum  to  the  spinal  column  and  con- 
tains all  the  thoracic  viscera  except  the  lungs  and  heart, 
that  is,  the  trachea,  esophagus,  thoracic  duct,  and  many 
large  vessels  and  nerves. 


FIG.  50. — Diagrammatic  representation  of  the  termination  of  a  bronchial 
tube  in  a  group  of  infundibular  B,  Bronchial  tube;  LB,  bronchiole;  A,  atrium; 
/,  infundibulum;  C,  alveoli,  (de  Nancrede.) 

Roughly  speaking,  the  lungs  begin  at  the  sterno- 
clavicular  articulation  above,  the  apex  coming  up  above 
the  level  of  the  first  rib,  and  extend  downward  together 
to  the  fourth  cartilage,  where  the  lower  margins  gradu- 
ally separate,  the  lowest  lung  limit  being  the  eleventh 
rib  in  the  vertebral  region.  Each  lung  is  conical.  The 
apices  extend  upward  and  the  bases,  which  are  broad 
and  concave,  rest  upon  the  diaphragm.  The  right  lung 
is  divided  by  a  fissure  into  three  lobes,  the  left  into 
two.  The  root  consists  of  a  bronchus  and  pulmonary 
arteries,  veins,  lymphatics,  and  nerves.  The  tissue 
itself  is  composed  of  an  aggregation  of  lobules,  each 
consisting  of  a  terminal  bronchiole  with  its  alveoli  or 
air  cells,  blood-vessels,  and  nerves,  a  lung  in  miniature. 


THE    LUNGS    AND    RESPIRATION.  127 

The  blind  pouches  which  the  air  cells  surround  are 
called  infundibula  and  are  separated  by  delicate  mem- 
branous septa  in  which  lie  the  capillaries  of  the  pulmo- 
nary artery,  thus  exposing  the  blood  to  the  air  on  two 
sides.  The  lung  itself  is  supplied  by  the  bronchial 
arteries  from  the  thoracic  aorta  and  by  branches  of  the 
sympathetic  and  pneumogastric  nerves. 

At  birth  the  lungs  are  pinkish-white  in  color  but  in 
later  life  they  are  marked  with  slate-colored  patches, 
due  to  the  deposit  in  the  lung  tissue  of  particles  of  dirt 
breathed  in.  They  are  light,  spongy,  and  highly  elas- 
tic, and  will  float  in  water,  crepitating  upon  pressure 
owing  to  the  air  in  the  tissue. 

At  birth,  also,  the  lungs  are  solid,  so  that  the  first 
air  has  to  overcome  adhesions  between  the  collapsed 
walls  of  the  bronchioles  and  air  sacs,  but  after  they 
are  thus  gradually  unfolded,  in  that  they  are  of  exten- 
sible material  and  open  to  the  air  above,  atmospheric 
pressure  from  within  keeps  them  distended  to  the  full 
extent  of  the  chest,  which  is  air  tight.  They  never  col- 
lapse afterwards  unless  puncture  of  the  chest  wall,  as 
in  stabbing,  causes  collapse,  in  which  case  the  lung 
shrivels  into  a  small  ball. 

Respiration. — That  the  organic  materials  used  by  the 
body  as  food  may  give  up  their  energy  they  must  be 
broken  up,  and  for  this  oxygen  is  needed.  The  supply 
of  oxygen  for  the  purpose  is  brought  to  the  tissues  by 
the  blood,  which  acquires  it  in  the  lungs,  and  the  waste 
product  of  combustion,  carbon  dioxide,  is  carried  off 
in  the  same  manner.  The  lungs  are,  therefore,  adapted 
to  take  in  large  quantities  of  air  and  to  keep  up  a  rapid 
exchange  of  oxygen  and  carbon  dioxide  in  the  blood. 
This  process  of  supplying  oxygen  to  the  tissues  and 
of  removing  carbon  dioxide  and  other  waste  is  ordi- 
narily an  involuntary  act,  though  it  can  be  regulated 
temporarily,  and  is  known  as  respiration  or  breathing. 

There  are  two  periods  to  respiration;  1.  inspira- 
tion or  the  drawing  in  of  air,  and  2.  expiration  or  the 


128  THE    LUNGS    AND    RESPIRATION. 

expulsion  of  air  from  the  lungs,  the  former  process  being 
a  little  shorter  than  the  latter.  A  pause  follows  each 
expiration  before  there  is  another  inspiration.  At 
birth  the  normal  rate  of  respiration  is  42,  but  it  grows 
slower  as  the  child  grows  older,  being  26  at  the  age  of 
five  or  six,  while  in  the  adult  it  averages  17  to  20  times 
a  minute.  It  is  slower  during  sleep  and  more  rapid 
during  physical  activity.  The  average  amount  of  air 
taken  in  with  every  inspiration  is  30  cubic  inches  and 
the  minimum  air  space  per  individual  should  be  3000 
cubic  feet  per  hour. 

Breathing  is  of  two  kinds,  diaphragmatic  or  abdom- 
inal and  chest  or  rib  breathing,  the  former  usually  being 
more  pronounced  in  men  than  in  women,  probably  be- 
cause of  centuries  of  tight  dressing  on  the  part  of  the 
latter.  As  a  rule,  however,  both  diaphragm  and  ribs 
come  into  play;  for  in  inspiration,  which  is  an  active 
movement,  the  thorax  becomes  enlarged  from  before 
backward,  laterally,  and  vertically.  The  ribs  are  raised 
by  the  external  intercostals  chiefly,  though  the  internal 
intercostals  aid  somewhat,  and  swinging  out  upon  the 
vertebrae,  widen  the  chest  as  well  as  deepen  it.  The 
diaphragm,  which  is  dome-like  when  relaxed,  becomes 
flattened  in  contraction  and  so  increases  the  size  of 
the  chest  from  above  downward.  As  the  chest  enlarges, 
the  lungs  expand,  the  air  in  them  becomes  rarefied,  and 
more  air  rushes  in.  When  the  lungs  are  full  they  re- 
lax and  the  muscles  relax  after  their  contraction,  so  that 
expiration  is  a  passive  movement,  due  largely  to  the 
elastic  relaxation  of  lungs  and  muscles,  the  air  being 
driven  out  by  the  lessened  capacity  of  the  lungs. 

Difficult  Breathing. — In  heart  and  lung  troubles, 
where  too  little  oxygen  is  carried  to  the  tissues,  dys- 
pnoea or  difficult  breathing  results  and  may  even  ad- 
vance to  asphyxia,  a  condition  in  which  no  air  is  ob- 
tained. In  difficult  or  labored  respiration  the  pectoral 
muscles  are  used  in  inspiration  and  the  scaleni,  which 
pass  from  the  vertebrae  of  the  neck  to  the  sternum, 


THE   LUNGS    AND    RESPIRATION.  129 

develop  and  become  powerful.  The  levatores  of  the 
ribs  may  also  assist,  and  even  the  muscles  of  the  neck 
and  arms  may  help  out,  while  in  forced  expiration  the 
abdominal  muscles  are  called  into  play.  The  glot- 
tis opens  and  closes  rhythmically  as  the  air  enters  and 
leaves  the  lungs,  and  the  nostrils  add  their  mite  in  the 
struggle  for  oxygen.  Finally  there  may  be  scarcely 
a  muscle  in  the  body  that  is  not  striving  to  aid  the  res- 
piration, and  general  convulsions  may  result,  followed 
by  exhaustion  and  death. 

Air. — In  ordinary  breathing  the  lungs  are  not  used 
to  their  full  capacity  and  the  air  ordinarily  used  is 
known  as  tidal  air.  In  forced  inspiration  the  lungs 
are  filled  to  their  fullest  extent  and  the  air  then  taken 
in  in  excess  of  the  tidal  air  is  known  as  complemen- 
ted air.  In  like  manner,  the  difference  between  the 
air  ordinarily  breathed  out  and  that  breathed  out 
in  forced  expiration  is  known  as  supplemental  air. 
The  sum  of  these  three  is  the  vital  capacity  of  the 
lungs,  while  beyond  this  there  is  probably  some  air 
that  is  never  expelled,  the  stationary  or  residual  air. 

Respiratory  Sounds. — The  entrance  and  exit  of  the 
air  is  accompanied  by  respiratory  sounds  or  murmurs, 
which  vary  according  to  their  position  in  the  trachea, 
the  bronchi,  or  the  bronchioles  and  are  modified  in 
diseases  of  the  lungs  and  bronchi,  when  they  are 
often  called  rales. 

Changes  in  Air  in  Lungs. — In  passing  through  the 
nose  and  the  rest  of  the  respiratory  tract  the  air  is 
warmed  to  body  temperature  and  saturated  with 
moisture.  After  its  entrance  into  the  lungs  various 
changes  take  place  in  it  through  the  mingling  of  the 
tidal  with  the  residual  air.  Thus,  it  gives  up  about  4  or 
5  per  cent,  of  its  oxygen  and  acquires  some  4  per  cent, 
additional  carbon  dioxide,  while  the  amount  of  nitro- 
gen remains  about  the  same.  By  its  giving  up  more 
oxygen  than  it  receives  carbon  dioxide,  its  volume 
is  slightly  diminished.  Exhaled  air  also  contains 


130  THE    LUNGS    AND    RESPIRATION. 

traces  of  ammonia  and  certain  organic  matters,  gen- 
erally the  results  of  decomposition,  which  give  a  bad 
odor  to  the  breath  and  are  more  dangerous  in  a  close 
room  than  the  mere  lack  of  oxygen  or  the  presence  of 
carbon  dioxide.  Indeed,  the  amount  of  oxygen  may 
be  very  much  diminished,  being  reduced  even  to  5  or 
6  per  cent,  instead  of  the  normal  21  per  cent.,  without 
being  noticed  or  giving  rise  to  any  immediate  bad  re- 
sults. Yet  the  import?  nee  of  ventilation  is  very 
evident. 

Effect  on  Blood. — Respiration  causes  changes  also  in 
the  blood,  the  venous  blood  being  purple  and  the  ar- 
terial bright  red.  This  difference  in  color  is  due  to  the 
absence  or  presence  of  oxygen,  which  is  not  absorbed 
or  dissolved  by  the  blood  but  forms  a  rather  unstable 
compound,  oxy hemoglobin,  with  the  hemoglobin  of 
the  blood.  As  the  oxgen  is  removed  in  the  passage 
of  the  blood  through  the  body,  there  results  in  venous 
blood  reduced  hemoglobin,  which  is  of  a  purplish 
color.  Upon  exposure  to  the  air,  however,  it  absorbs 
oxygen  once  more  and  resumes  its  scarlet  color.  If 
carbon  monoxide  gets  into  the  blood,  as  in  cases  of 
gas  poisoning,  it  drives  off  the  oxygen  and  forms  a 
more  stable  compound  with  the  hemoglobin,  whence 
the  difficulty  in  restoring  a  person  so  poisoned. 

Nervous  Mechanism. — Nervously,  respiration  is  con- 
trolled in  three  ways:  1.  by  the  phrenic  nerve  to 
the  diaphragm;  2.  by  some  fibers  of  the  vagus  or 
pneumogastric,  and  3.  by  the  respiratory  center  in  the 
bulbous  portion  of  the  spinal  cord.  Injury  to  the  res- 
piratory center  means  the  ceasing  of  respiration  and 
death.  Stimulation  of  the  respiratory  center  seems 
to  depend  upon  the  character  of  the  blood.  If  it  is 
well  oxygenized,  the  breathing  is  slow  and  quiet;  if 
there  is  a  lack  of  oxygen,  dyspnoea  results.  Probably 
certain  chemical  substances  in  the  blood,  which  are 
ordinarily  rapidly  burned  up  by  the  oxygen  but  which 
accumulate  in  its  absence,  serve  to  stimulate  the 


THE    LUNGS    AND    RESPIRATION.  131 

respiratory  center,  thus  adjusting  the  effort  to  get  oxy- 
gen to  the  need  of  it.  Respiration  may  be  stopped 
by  stimulating  the  mucous  membrane  of  the  nose,  as 
with  strong  ammonia. 

Variations. — Certain  variations  from  the  ordinary 
respiration  might  be  mentioned  here.  A  deep  inspira- 
tion followed  by  a  long  expiration  is  known  as  a  sigh 
and  a  very  deep  inspiration  through  the  mouth  only  as 
a  yawn.  Hiccough  results  from  a  sudden  inspiratory  con- 
traction of  the  diaphragm  during  which  the  glottis  is 
suddenly  closed.  In  sobbing  the  inspirations  are  short 
and  rapid  with  a  prompt  closing  of  the  glottis  be- 
tween. Both  coughing  and  sneezing  consist  of  a  deep 
inspiration  followed  by  complete  closure  of  the  glot- 
tis and  then  its  sudden  opening  and  the  forcible  ex- 
pulsion of  air.  Coughing,  however,  is  generally  caused 
by  an  irritation  or  obstruction  of  the  larynx  or  trachea 
and  the  air  is  expelled  through  the  mouth,  while  sneez- 
ing is  caused  by  irritation  of  the  nasal  passages  and  the 
air  is  driven  out  through  the  nose.  Laughing  and 
crying  also  resemble  one  another  in  that  each  is  an  in- 
spiration followed  by  a  series  of  short,  spasmodic  ex- 
pirations, during  which  the  glottis  is  open  and  the 
vocal  cords  in  characteristic  vibration.  They  differ, 
however,  in  rhythm  and  in  the  facial  expression  that 
accompanies  them. 


CHAPTER  X. 

THE  ABDOMEN  AND  THE  ORGANS  OF 
DIGESTION  AND  EXCRETION. 

The  Abdominal  Cavity. — Below  the  diaphragm  and 
separated  from  the  lowest  cavity  of  the  trunk,  the 
pelvis,  only  by  an  invisible  plane  drawn  through  the 
brim  of. the  true  pelvis,  is  the  abdominal  cavity,  which 
may  be  said  in  a  general  way  to  contain  the  organs 
of  digestion  and  the  kidneys.  It  is  protected  behind 
by  the  vertebrae  and  anteriorly  by  the  lower  ribs  above 
and  below  by  muscular  walls,  which  make  possible  the 
complete  bending  of  the  body.  These  muscles  are 
for  the  most  part  large  and  very  strong  and  the  greater 
number  are  inserted,  in  part  at  least,  into  a  median 
tendinous  line,  the  linea  alba,  which  passes  from  the 
ensiform  cartilage  of  the  sternum  above  to  the  sym- 
physis  pubis  below. 

Muscles. — The  external  obligue  muscles  form  the  outer- 
most layer  of  the  abdominal  wall.  They  rise  from 
the  external  surface  of  the  eight  lower  ribs  on  either 
side  and  are  inserted  in  the  anterior  half  of  the  iliac 
crest  as  well  as  by  aponeurosis  in  the  linea  alba,  where 
each  joins  its  fellow  from  the  opposite  side,  the  fibers 
running  downward  and  inward  like  the  fingers  in  the 
trouser's  pocket.  Along  the  lower  border  of  the  apo- 
neurosis is  a  broad  fold,  Poupart's  ligament.  The  in- 
ternal oblique  rises  on  either  side  from  the  outer  half 
of  Poupart's  ligament  and  the  anterior  part  of  the  crest 
of  the  ilium  and  is  inserted  into  the  crest  of  the  os  pubis, 
the  cartilages  of  the  lower  ribs,  and  the  linea  alba. 
Its  fibers  run  at  right  angles  to  those  of  the  external 
oblique.  These  oblique  muscles  serve  to  compress  the 
viscera,  to  flex  the  body,  and  also  assist  in  expiration. 

132 


THE   ABDOMEN. 


133 


The  deepest  of  the  abdominal  muscles  is  the  trans- 
versalis,  which  rises  from  the  outer  third  of  Poupart's 
ligament  and  the  adjoining  part  of  the  crest  of  the 
ilium,  from  the  six  lower  costal  cartilages,  and  by  a 


FIG.  51. — Muscles  of  the  trunk  from  before  (left  side,  superficial;  and  right 
side,  deep):  1,  Pectoralis  major;  2,  deltoid;  3,  portion  of  latissimus  dorsi;  4, 
serratus  magnus;  5,  subclavius;  6,  the  pectoralis,  sternocostal  portion;  7,  serratus 
magnus;  12,  rectus  abdominis;  13,  internal  oblique;  14,  external  oblique;  15, 
abdominal  aponeurosis  and  tendinous  intersections  of  rectus  abdominis;  16,  over 
symphysis  pubis;  17,  linea  semilunaris;  18,  gluteus  medius;  19,  tensor  vaginse 
femqris;  20,  rectus-  femoris;  21,  sartorius;  22,  femoral  part  of  iliopsoas;  23, 
pectineus;  24,  adductor  longus;  25,  gracilis.  (Borland's  Dictionary.) 

broad  aponeurosis,  the  lumbar  fascia,  from  the  lumbar 
vertebrae.  It  is  inserted  into  the  pubic  crest  and  by 
aponeurosis  into  the  linea  alba.  There  is  one  of  these 
muscles  on  either  side. 

The  rectus  abdominis  is  also  really  two  muscles  and 


134  THE    ABDOMEN. 

extends  from  the  symphysis  pubis  to  the  cartilages 
of  the  fifth,  sixth,  and  seventh  ribs.  At  first  it  passes 
back  of  the  oblique  and  transversalis  muscles,  but  about 
a  fourth  of  the  way  up  it  passes  in  front  of  the  trans- 
versalis and  between  two  layers  of  the  internal  oblique, 
which  thereafter  forms  its  sheath.  Its  chief  duty  is  to 
flex  the  chest  on  the  pelvis,  though  it  also  compresses 
the  abdominal  viscera. 

One  other  muscle,  a  small  one,  is  found  in  front,  the 
pyramidalis ,  which  rises  from  the  pubic  crest  and  is  in- 
serted into  the  linea  alba  midway  to  the  umbilicus. 

At  the  back  the  open  space  over  the  kidneys,  between 
the  lower  ribs  and  the  os  innominatum,  is  closed  in  on 
either  side  by  the  quadratus  lumborum,  which  extends 
from  the  three  or  four  lower  lumbar  vertebrae  and  the 
adjacent  iliac  crest  to  the  last  rib  and  the  upper  four 
lumbar  vertebrae.  It  flexes  the  trunk  laterally  or  forward 
according  as  one  muscle  or  both  are  used,  and  may  aid 
in  either  expiration  or  inspiration. 

The  nerves  of  the  abdominal  muscles  are  chiefly  the 
internal  intercostals. 

The  Peritoneum. — Lining  the  abdominal  cavity  is  a 
serous  membrane,  the  peritoneum,  which  is  reflected 
back  over  the  viscera  within  in  such  a  way  as  to  cover 
each  one  wholly  or  in  part.  Folds  of  peritoneum,  the 
omenta,  connect  the  stomach  with  the  other  viscera,  the 
most  important  being  the  great  omentum,  which  has  one 
layer  descending  from  the  anterior  and  another  from  the 
posterior  wall  of  the  stomach.  The  mesenteries  are 
double  layers  of  peritoneum  which  hold  the  intestines 
to  the  vertebrae  and  posterior  wall.  Between  their  folds 
run  the  blood-vessels. 

Abdominal  Regions. — For  convenience  of  description 
the  abdominal  cavity  has  been  divided  into  nine  regions 
by  means  of  two  transverse  paralled  lines,  the  one  through 
the  ninth  costal  cartilages  and  the  other  just  over  the 
iliac  crests,  and  two  perpendicular  parallel  lines  through 
the  cartilage  of  the  eighth  rib  and  the  middle  of  Poupart's 


THE    ABDOMEN.  135 

ligament  on  either  side.  These  nine  regions  have  been 
named  as  follows:  The  right  and  left  hypochondriac 
regions  up  under  the  ribs  with  the  epigastrium  between, 
the  right  and  left  lumbar  regions  next  below  with  the 
umbilical  between,  and  the  right  and  left  inguinal  with 


FIG.  52. — Diagram  showing  the  nine  regions  of  the  abdominal  cavity: 
1,  Right  hypochondriac;  2,  epigastric;  3,  left  hypochondriac;  4,  right 
lumbar;  5,  umbilical;  6,  left  lumbar;  7,  right  iliac;  8,  hypogastric;  9,  left 
iliac.  (Ashton.) 


the  hypogastric  between.  Others  divide  it  into  quad- 
rants by  one  line  drawn  across  and  another  down  through 
the  umbilicus.  The  contents  of  the  abdomen  in  full  are 
the  stomach,  intestines,  liver,  gall-bladder,  spleen,  pan- 
creas, kidneys,  suprarenal  capsules,  and  the  great  vessels, 
that  is,  the  organs  of  digestion  and  excretion.  When  dis- 


136  THE    ABDOMEN. 

tended  the  bladder  extends  up  into  the  abdominal  cav- 
ity, as  does  the  uterus  also  when  enlarged. 

Salivary  Digestion. — Although  most  of  the  digestive  or- 
gans are  situated  in  the  abdomen,  the  food  enters  the  body 
through  the  mouth,  where  its  prehension  is  a  voluntary 
act.  Here  digestion  also  begins  and  from  the  first  the 
process  is  a  double  one,  mechanical  and  chemical,  me- 
chanical digestion  consisting  largely  of  muscular  move- 
ments by  which  the  food  is  ground  up  and  carried  through 
the  digestive  tract.  Thorough  mastication  or  grinding 
of  the  food  by  the  teeth  is  necessary,  while  the  tongue 
assists  by  moving  the  food  about  and  by  mixing  it 
thoroughly  with  the  saliva,  a  viscid  fluid  composed  of 
water  and  salts  and  having  a  slightly  alkaline  reaction. 
The  saliva  is  secreted  by  the  parotid,  sublingual,  and 
submaxillary  glands,  and  serves  to  soften  and  dissolve  the 
food  and  by  virtue  of  its  unorganized  ferment,  ptyalin,  to 
convert  starch  into  sugar.  Upon  proteins  and  fats  it  has 
practically  no  digestive  action.  Moderate  warmth  and 
an  alkaline  medium  favor  its  action,  while  extremes  of 
heat  or  cold  or  an  acid  medium  hinder  it.  There  is  little 
absorption  in  the  mouth,  though  starch,  nicotine,  and 
alcohol  may  be  absorbed  in  small  quantities. 

The  Pharynx. — When  the  food  is  ready  for  deglutition 
or  swallowing,  it  is  thrust  back  into  the  pharynx,  a  some- 
what conical,  musculo-membranous  sac,  situated,  base 
upward,  behind  the  nose  and  mouth  and  behind,  but 
somewhat  above,  the  larynx.  The  pharynx  is  about  four 
and  a  half  inches  long  and  ends  on  a  level  with  the 
cricoid  cartilage  in  the  esophagus  or  gullet.  It  is  at- 
tached to  the  vertebrae  at  the  back  and  opens  in  front 
into  the  mouth.  The  posterior  nares,  the  Eustachian 
tubes,  and  the  larynx  also  open  into  it,  the  last  being  pro- 
tected by  the  epiglottis,  which  closes  during  deglutition 
to  prevent  food  from  entering  the  air  passages,  just  as 
the  soft  palate  is  drawn  back  to  prevent  regurgitation  of 
food  into  the  nose.  There  are  three  coats  to  the 
pharynx;  1.  a  mucous  coat  continuous  with  that  of  the 


THE    ABDOMEN. 


137 


mouth  and  ciliated  down  to  the  floor  of  the  nares;  2.  a 
fibrous  coat,  and  3.  a  muscular  coat  containing  among 
others  the  constrictor  muscles  which  serve  to  carry  the 
food  down  to  the  esophagus.  Its  arteries  are  branches 


FIG.  53.— Position  of  the  thoracic  and  abdominal  organs,  front  view 
(Morrow.) 

of  the  external  carotid  and  its  nerves  come  from  the 
spinal  accessory  and  the  sympathetic.  Occasionally  a 
foreign  body  gets  lodged  in  the  pharynx  just  out  of  reach 
of  the  finger  and  threatens  strangulation.  Retropharyn- 
geal  abscess  on  the  posterior  wall  occurs  rarely. 


138  THE    ABDOMEN. 

The  Esophagus. — From  the  pharynx  the  food  passes  to 
the  cardiac  orifice  of  the  stomach,  opposite  the  tenth 
dorsal  vertebra,  through  the  esophagus,  a  muscular  tube 
about  nine  inches  long,  which  collapses  when  empty,  its 
lumen  then  appearing  as  a  transverse  slit.  It,  too,  has 
three  coats:  1.  an  inner  mucous  coat;  2.  an  areolar  coat, 
and  3.  a  muscular  coat,  the  muscles  being  arranged  in  two 
sets,  an  outer  longitudinal  layer  and  an  inner  circular 
layer.  By  a  series  of  ryhthmic  contractions,  especially 
of  the  circular  fibers,  the  food  is  pushed  along,  though 
sometimes  with  liquid  food  there  is  no  peristaltic  action 
of  the  esophagus,  the  pharyngeal  muscles  alone  sending 
it  to  the  stomach.  At  the  lower  end  of  the  esophagus  an 
especially  strong  band  of  circular  muscle  fibers  form  a 
sort  of  sphincter,  which  prevents  the  regurgitation  of 
food.  The  whole  act  of  swallowing  is  a  reflex,  not  a 
voluntary,  act  and  is  due  to  irritation  set  up  by  the 
stimulus  of  the  foreign  body,  the  food.  Stricture  of  the 
esophagus  is  common  and  may  be  of  three  kinds:  1.  spas- 
modic, occurring  in  nervous  women;  2.  fibrous,  due  to 
scar  tissue,  or  3.  malignant,  due  to  cancer. 

The  Stomach. — The  stomach  is  a  pear-shaped  dilata- 
tion of  the  alimentary  canal,  lying  under  the  liver  and 
diaphragm  in  the  epigastrium  and  left  hypochondrium 
and  connecting  the  esophagus  with  the  small  intestine. 
It  lies  largely  behind  the  ribs,  but  the  greater  curvature 
is  only  two  fingers'  breadth  above  the  umbilicus  and  can 
be  manipulated  through  the  skin.  The  cardiac  end,  into 
which  the  esophagus  enters,  is  the  larger  and  points 
upward  to  the  left.  The  lesser  and  lower  end,  known  as 
the  pylorus,  is  at  the  right  and  its  opening  into  the  small 
intestine  is  guarded  by  the  pyloric  sphincter.  The  lesser 
curvature  is  concave  and  on  the  upper  surface;  the  greater, 
convex  and  on  the  under  surface.  The  great  omentum 
is  attached  to  the  latter. 

In  size  the  stomach  varies  more  or  less,  that  of  a  man 
generally  being  larger  than  that  of  a  woman,  but  it  is 
usually  about  ten  inches  long  and  four  or  five  inches 


THE    ABDOMEN.  139 

across.  It  has  a  capacity  of  about  five  pints  and  serves 
as  a  storehouse  for  food. 

The  stomach  has  four  coats:  1.  a  serous  coat  derived 
from  the  peritoneum;  2.  a  muscular  coat  of  three  layers 
with  longitudinal  fibers  continuous  with  those  of  the 
esophagus,  circular  fibers,  and  oblique  fibers;  3.  an  areolar 
coat,  and  4.  a  mucous  coat,  which,  when  the  stomach  is 
empty,  is  thrown  into  longitudinal  folds  or  rugce,  and 
whose  surface  is  covered  with  glands,  the  gastric  glands, 
for  the  secretion  of  the  digestive  fluids. 

The  arteries  come  from  the  celiac  axis  and  the  nerves 
from  the  pneumogastric  and  the  solar  plexus. 

Ulcer  and  cancer  of  the  stomach  are  both  rather  com- 
mon. In  the  former  there  is  apt  to  be  hyper-acidity  and 
in  the  latter  %jw>-acidity,  but  the  rule  does  not  always 
hold.  In  cases  of  ulcer  there  may  be  hemorrhage  and 
even  perforation.  Such  hemorrhage  can  be  distinguished 
from  hemorrhage  from  the  lungs  by  its  slightly  acid  odor 
and  by  the  frothy  character  of  hemorrhage  from  the 
lungs.  There  is  much  irritation  at  the  pylorus  and  where 
there  is  irritation  there  is  liable  to  be  cancer. 

Gastric  Digestion. — In  the  stomach  the  food  is  churned 
and  thoroughly  mixed  with  the  gastric  juices,  and  it  is 
also  subjected  to  a  propulsive  movement  that  drives  it  on 
to  the  intestine.  When  it  comes  to  the  stomach  it  is  semi- 
solid  and  when  it  has  become  fluid  or  semi-fluid,  in  which 
state  it  is  known  as  chyme,  it  is  ready  to  pass  on.  Before 
it  can  do  so,  however,  it  must  overcome  the  strong  pyloric 
sphincter,  and  this  it  does  by  the  muscles  about  the 
sphincter  pushing  it  constantly  on  until  the  sphincter 
gives  way.  Probably  most  of  the  propulsive  movements 
take  place  within  a  few  inches  of  the  pylorus. 

The  gastric  juice  is  secreted  by  glands  in  the  wall  of  the 
stomach  and  poured  out  through  little  tubules  which 
project  from  the  surface.  It  is  a  thin,  almost  colorless 
fluid  with  a  sour  taste  and  odor  due  to  the  presence  of  free 
hydrochloric  acid,  an  important  element  in  digestion. 
Probably  when  the  stomach  is  empty  and  for  some  twenty 


140  THE  A&DOMEN. 

minutes  after  the  appearance  of  food  there  is  no  hydro- 
chloric acid  present  and,  the  food  being  alkaline,  salivary 
digestion  continues.  Then,  called  forth  by  the  presence 
of  the  food,  the  hydrochloric  acid  appears  and  salivary 
digestion  ceases  in  the  acid  medium.  Little  digestion 
of  starches  or  fats  takes  place,  the  chief  action  being  on 
proteins,  which  are  converted  into  soluble  peptones. 
For  besides  hydrochloric  acid  the  gastric  juice  contains 
two  ferments:  1.  pepsin,  which  is  particularly  active  in 
aiding  the  digestion  of  proteins,  and  2.  rennin,  which 
especially  affects  milk.  Neither  hydrochloric  acid  nor 
pepsin  seems  capable  of  digesting  food  alone,  but  each 
is  essential  to  the  other.  They  are  secreted  by  different 
types  of  cells,  secretion  depending  upon  the  nerve  supply 
and  upon  the  presence  of  food.  Gastric  digestion  is 
favored  by  minute  subdivision  of  the  food  and  by  the 
right  proportion  of  hydrochloric  acid,  which  should  be 
0.2  per  cent.  Body  temperature  is  also  advantageous. 
Except  that  proteins  are  put  in  solution  and  partly  di- 
gested, little  digestion  goes  on  in  the  stomach,  and  though 
the  rugae  afford  a  large  absorbing  surface,  little  absorption 
takes  place,  although  more  takes  place  than  in  the  mouth 
and  in  time  most  foods,  except  fats,  can  be  absorbed. 
The  time  of  digestion  varies  with  different  foods  and  in 
different  poeple,  but  probably  three  to  five  hours  are 
necessary.  The  food  leaves  the  stomach  as  chyme,  a 
fluid  of  about  the  consistency  of  pea  soup. 

Vomiting  is  more  or  less  the  reverse  of  swallowing  and 
is  generally  preceded  by  a  feeling  of  nausea,  which  starts 
up  retching,  a  more  or  less  involuntary  effort  of  the  stom- 
ach to  throw  off  its  contents.  To  relieve  the  retching  a 
long  breath  is  taken,  followed  by  a  deep  expiration  that 
opens  the  cardiac  end  of  the  stomach  and  allows  the 
abdominal  muscles  to  force  the  food  out.  After  much 
vomiting  and  prolonged  retching  the  pyloric  end  of  the 
stomach  may  be  affected  and  bile  will  then  appear  in  the 
vomitus.  Artificial  vomiting  may  be  produced  by  irrita- 


THE    ABDOMEN.  141 

tion  of  the  gastric  nerve  center  in  the  brain  or  by  irrita- 
tion of  the  stomach  itself. 

Intestinal  Canal. — From  the  stomach  the  food  passes 
into  the  intestinal  canal,  a  convoluted  tube  which  extends 
from  the  stomach  to  the  anus  and  in  which,  more  partic- 
ularly in  the  upper  portion,  the  greater  part  of  the  diges- 


FIG.  54. — The  intestinal  canal:  1,  Stomach;  2,  duodenum;  3,  jejunum;  4, 
ileum;  5,  cecum;  6,  vermiform  appendix;  7,  ascending  colon;  8,  transverse 
colon;  9,  descending  colon;  10,  sigmoid  flexure;  11,  rectum.  (Leidy.) 

tion  and  absorption  of  food  takes  place.  This  tube, 
which  is  about  six  times  the  height  of  its  possessor,  con- 
sists of  two  parts,  the  small  and  the  large  intestines,  the 
first  four-fifths,  or  about  25  feet,  being  small  intestine. 
It  occupies  the  central  and  lower  parts  of  the  abdominal 
cavity  and  a  small  portion  of  the  pelvic  cavity,  and  is 
attached  to  the  spine  by  the  mesentery,  which,  however, 


142  THE    ABDOMEN. 

allows  great  freedom  of  motion,  so  that  there  is  little 
fixation  to  the  loops  of  the  small  intestines. 

The  Small  Intestine. — The  small  intestine  opens  out  of 
the  stomach  and  has  three  divisions:  1.  the  duodenum, 
which  is  only  about  ten  to  twelve  inches  long;  2.  the  jeju- 
num, so  called  because  it  is  generally  empty  after  death, 
which  is  about  two-fifths  of  the  remainder  and  lies  chiefly 
in  the  umbilical  region  and  the  left  iliac  fossa,  and  3.  the 
ileum  or  curved  intsstine,  the  remaining  three-fifths,  which 
gets  its  name  from  its  numerous  coils  and  which  lies  in 
the  middle  and  the  right  side  of  the  abdomen.  There  is 
no  direct  division  between  the  jejunum  and  the  ileum,  but 
the  first  part  of  the  former  and  the  last  part  of  the  latter 
are  quite  different  in  character.  At  its  entrance  into  the 
large  intestine  the  ileum  is  guarded  by  the  ileo-cecal 
valve. 

The  same  coats  continue  in  the  small  intestine  as  were 
found  in  the  stomach,  but  they  are  here  much  thinner  and 
the  inner  coat  is  shaggy,  like  velvet,  with  innumerable 
minute  processes  called  mlli,  which  greatly 
increase  the  absorbing  surface.  In  fact, 
the  great  length  of  the  intestine  as  well  as 
the  presence  of  the  villi  is  aimed  to  pro- 
vide a  large  surface  to  absorb  the  food  as 
it  passes,  an  even  greater  increase  of  sur- 
face being  provided  by  the  fact  that  the 
tr^i10' licteai-' °e2  intestinal  wall  is  thrown  into  folds,  the 
capillary  network!  valvulce  conniventes.  Each  villus  is  covered 

3,  columnar  cells.          . .,       ,  r>       i  «ji     T    i       n  i 

with  a  layer  of  columnar  epithelial  cells  and 
has  within  connective  tissue,  in  which  are  found  a  fine 
capillary  network  and  open  lymph  spaces  from  which 
leads  a  single  lacteal  vessel. 

Closely  connected  with  the  lymphatic  vessels  are  the 
solitary  glands,  small  round  bodies  the  size  of  a  small  pin's 
head.  Peyer's  glands  or  patches  are  patches  of  solitary 
glands  opposite  the  mesenteric  attachment  and  are 
largest  and  most  numerous  in  the  ileum.  In  typhoid 
fever  they  are  involved  and  may  become  the  seat  of 


THE    ABDOMEN.  143 

ulcers.  There  are  also  the  glands  of  Lieberkiihn  which 
secrete  the  succus  entericus. 

The  arteries  of  the  small  intestine,  which  include  the 
superior  mesenteric,  are  from  the  celiac  axis  and  the 
nerves  are  from  the  superior  mesenteric  plexus  of  the 
sympathetic.  The  veins  empty  chiefly  into  the  portal 
system. 

The  movements  of  the  intestine,  like  those  of  the 
esophagus,  are  peristaltic,  but  the  action  is  complicated 
by  the  fact  that  the  tube  is  not  straight  but  in  coils. 

Intestinal  Digestion. — The  food,  which  enters  the  duo- 
denum as  chyme,  there  comes  in  contact  with  the  bile  and 
the  pancreatic  juice,  which  together  but  unmixed  enter  the 
duodenum  from  their  respective  ducts  by  a  common  orifice. 
As  in  the  stomach,  the  digestive  juices  are  called  forth  by 
the  presence  of  food.  The  bile  is  secreted  in  the  liver,  from 
which  it  flows  away  through  the  hepatic  duct,  which  joins 
the  cystic  duct  from  the  gall-bladder  to  form  the  common 
bile  duct.  Through  this  it  flows  into  the  intestine  during 
digestion,  but  between  whiles  it  passes  up  into  the  gall- 
bladder, where  it  is  stored  for  future  use  and  whence  it  is 
expelled  when  needed.  When  pure  it  is  a  thick,  viscid 
liquid,  varying  from  a  bright  red  to  a  greenish-yellow  in 
color  according  to  the  pigments  present,  and  of  an  alka- 
line reaction.  It  consists  chiefly  of  the  bile  pigments, 
biliverdin,  which  gives  the  green  color,  and  bilirubinf 
which  gives  the  red  color,  and  of  bile  salts  in  solution. 
cholesterin,  which  probably  forms  the  basis  of  many  gall 
stones,  is  also  present.  Bile  is  a  disinfectant  to  the  bowel 
and  a  lubricant  for  the  feces.  How  much  digestive 
action  it  has  is  a  question,  but  it  affords  the  necessary 
alkaline  medium  for  the  pancreatic  juice  to  act  in. 

The  pancreatic  juice  is  secreted  by  the  pancreas,  from 
which  it  enters  the  intestine  through  the  pancreatic  duct, 
and  is  probably  the  most  important  fluid  in  the  digestive 
process.  It  is  clear,  practically  colorless,  slightly  viscid 
or  gelatinous,  and  quite  strongly  alkaline  in  reaction, 
owing  to  the  presence  of  sodium  carbonate.  It  contains 


144  THE    ABDOMEN. 

three  ferments,  amylopsin  for  the  digestion  of  starch, 
trypsin  for  the  digestion  of  proteins,  and  steapsin  for  tho 
digestion  of  fats.  By  it,  as  by  the  saliva,  starch  is  turned 
into  sugar  or  maltose,  in  which  form  it  is  absorbed,  while 
proteins  are  converted  into  peptones,  as  they  are  in  the 
stomach.  Since,  however,  fats  are  acted  on  nowhere  else, 
the  chief  function  of  the  pancreatic  juice  may  be  con- 
sidered to  be  the  digestion  of  fats.  Having  broken 
through  their  albuminous  envelope,  it  divides  them  into 
glycerine  and  fatty  acids  and  then  emulsifies  them  with 
the  assistance  of  the  bile. 

The  food  also  comes  in  contact  with  the  succus  enteri- 
cus,  a  juice  secreted  by  the  glands  of  Lieberkiihn  in  the 
small  intestine,  whose  chief  action  is  the  conversion  of 
sugar  into  glucose. 

Absorption. — As  the  food  is  absorbed  from  the  intes- 
tine it  is  liquid  and  entirely  digested  and  is  known  as 
chyle.  Practically  all  absorption  takes  place  from  the 
small  intestine,  though  there  is  a  little  in  the  large  in- 
testine. It  takes  place  in  two  ways:  1.  through  the  por- 
tal vessels  and  2.  through  the  lacteals,  which  are  the 
lymphatic  vessels  of  the  small  intestine.  Fats  are  ab- 
sorbed practically  entirely  by  the  lacteals.  They  enter 
the  cells  covering  the  villi,  travel  thence  to  the  lymph 
spaces,  and  so  into  the  lacteal  or  main  lymph  channel, 
whence  they  are  carried  to  the  thoracic  duct  and  the 
general  circulation.  From  the  blood  they  are  absorbed 
as  fat  and  stored  up  as  adipose  or  fatty  tissue,  which  is 
found  throughout  the  body  in  connective  tissue  about 
the  organs.  Organic  salts  and  water  are  for  the  most 
part  absorbed  by  the  portal  system,  which  they  reach 
through  the  capillaries  of  the  villi  and  through  which 
they  go  to  the  liver.  Starches,  in  the  form  of  sugar, 
pass  between  the  cells  of  the  villi  into  the  lymph  spaces, 
from  which  they  are  taken  up  by  the  capillaries.  On  the 
way  to  the  liver  maltose  becomes  dextrose.  Proteins, 
in  the  form  of  peptones,  pass  through  the  layer  of 
epithelial  cells  to  the  lymph  spaces  and  then  to  the 


THE    ABDOMEN.  145 

capillaries,  an  active  part  being  taken  by  the  cells.  By 
the  time  they  reach  the  liver  the  peptones  have  been 
changed  back  into  proteins.  In  fact,  peptones  seem  to 
have  some  poisonous  effect  upon  the  blood  if  they  get 
into  it  as  such. 

The  Large  Intestine. — The  large  intestine  differs  from 
the  small  in  size  and  in  fixity  of  position,  lying  curved  in 
horseshoe  shape  above  and  around  the  small  intestine. 
It  is  five  or  six  feet  long,  large  in  caliber,  and  is  thrown 
into  crosswise  folds.  It  has  the  same  four  coats  as  the 
small  intestine,  but  the  mucous  coat  is  pale  and  smooth, 
without  villi.  Its  glands  are  the  crypts  of  Lieberkiihn 
and  the  solitary  glands.  The  arteries  are  branches  of  the 
superior  and  inferior  mesenteric  and  the  nerves  come 
from  sympathetic  plexuses. 

The  blind  sac  lying  in  the  right  iliac  fossa,  with  which 
the  large  intestine  begins,  is  called  the  cecum,  and  into 
this  the  ileum  opens,  the  ileo-cecal  valve  preventing 
regurgitation.  Just  below  the  ileo-cecal  opening  is  the 
vermiform  appendix,  a  narrow,  worm-like  tube  with  a 
blind  end,  varying  in  length  from  one  to  nine  inches,  but 
generally  about  four  and  one-half  inches  long,  which,  so 
far  as  is  known,  is  functionless  as  well  as  dangerous. 
People  have  been  born  without  an  appendix  and  it  has 
in  rare  instances  grown  again  after  operation.  Its  base 
is  located  in  the  living  by  McBurney's  point,  a  point  two 
inches  from  the  anterior  superior  spine  of  the  ilium  on 
a  line  drawn  from  the  spine  to  the  umbilicus. 

From  the  cecum  the  intestine  ascends  in  what  is  known 
as  the  ascending  colon  along  the  abdominal  wall  at  the 
right  to  the  under  surface  of  the  liver,  where  it  turns 
in  the  hepatic  flexure  abruptly  across  the  body  to  the 
left,  passing  below  the  liver,  stomach,  and  spleen  in 
the  transverse  colon.  In  the  splenic  flexure  it  turns  down 
the  left  abdominal  wall,  the  descending  colon  passing  to 
the  crest  of  the  ilium,  where  there  is  another  curve, 
the  sigmoid  flexure,  leading  to  the  rectum,  which  passes 
for  six  or  eight  inches  down  along  the  vertebrae,  a  little 
10 


146  THE  ABDOMEN. 

to  the  left,  to  the  anus,  the  external  opening.  This 
opening  is  guarded  by  two  sphincter  muscles,  about  an 
inch  apart,  the  internal  and  external  sphincters.  The 
coils  of  the  small  intestine  lie  below  the  transverse  colon, 
covered  mostly  by  the  omentum.  The  splenic  flexure  is 
behind  the  stomach  and  below  the  spleen  and  is  slightly 
higher  than  the  hepatic  flexure.  The  sigmoid  flexure 
can  be  felt  in  the  left  inguinal  region  in  thin  people. 

The  fact  that  the  rectum  is  somewhat  to  the  left  is  of 
importance  in  childbirth  because  if  the  rectum  is  packed, 
it  may  turn  the  child's  head  in  the  wrong  direction. 

No  digestion  goes  on  in  the  large  intestine,  the  func- 
tion being  to  dry  by  absorbing  water.  The  movements 
are  practically  the  same  as  those  of  the  small  intestine 
except  that  they  are  much  less  active.  Fermentation 
makes  the  contents  acid.  By  the  time  food  reaches  the 
rectum  it  has  been  thoroughly  digested  and  has  given  up 
its  nourishment.  It  is  then  expelled  as  waste  matter  or 
feces.  Defecation  combines  the  involuntary  movements 
of  peristalsis  and  relaxation  of  the  sphincters  with  the 
voluntary  aid  of  the  abdominal  muscles.  The  ano-spinal 
reflex,  by  which  movements  of  the  bowel  are  regulated, 
is  in  the  lumbar  enlargement  of  the  cord. 

The  hemorrhoidal  veins  in  the  lower  rectum  are  con- 
nected with  both  the  systemic  and  the  portal  veins  and 
have  no  valves  so  that,  as  they  are  subjected  to  much 
strain,  they  often  become  varicose  and  dilated.  This 
condition  is  called  hemorrhoids  or  piles.  Obstruction  of 
the  intestine  may  be  caused  by  the  growth  of  a  con- 
stricting band,  by  intussusception  or  telescoping  of  the 
intestine  on  itself,  especially  at  the  ileocecal  valve,  or  by 
volvulus  or  twisting.  Foreign  bodies  are  sometimes  found 
in  the  appendix  but  they  are  not  usually  the  cause  of 
appendicitis.  Cancer  of  the  intestine  is  common  and  its 
mass  is  apt  to  cause  obstruction  with  all  its  attendant 
symptoms.  It  may  necessitate  an  artificial  anus. 
Hernia  or  rupture  may  also  occur  and  the  hernia  may 
become  strangulated. 


THE    ABDOMEN.  147 

Food  and  Metabolism. — Anything  serves  as  food  that 
replaces  or  hinders  the  loss  to  which  the  component  parts 
of  the  body  are  liable.  Proteins,  carbohydrates,  fats, 
some  mineral  matters,  as  salt  and  perhaps  iron,  and  water 
are  needed.  The  energy  once  expended  by  plants  or 
animals  in  the  formation  of  the  materials  which  serve  as 
food  is  set  free  in  the  body  by  the  breaking  up  of  these 
complex  substances  into  their  original  elements,  which 
are  then  recombined  into  the  complex  materials  needed 
for  the  body's  life  and  growth.  This  process  of  building 
up  complex  materials  from  simple  ones  is  known  as 
anabolism  and  that  of  breaking  them  down  as  katabolism, 
while  the  two  combined  form  the  complete  cycle  of 
metabolism.  Those  foods  have  the  best  value  that  give 
up  their  energy  most  readily.  For  their  combustion, 
heat,  oxygen,  and  water  are  needed.  Hunger  indicates 
that  the  supply  of  material  for  katabolism  has  been  used 
up  and  that  more  is  needed,  just  as  thirst  indicates  the 
need  of  the  system  for  more  fluids. 

The  proteins  or  nitrogenous  foods  include  all  animal 
foods  except  fats,  fish,  crustaceans,  eggs,  milk  and  its 
products,  certain  vegetables,  especially  the  lentils,  that 
is,  peas  and  beans,  and  gelatine.  The  fats  include  various 
fats  and  oils  commonly  eaten.  The  carbohydrates  are 
the  starchy  foods,  as  cereals,  sugars,  fruits,  and  most 
vegetables,  in  fact,  practically  all  except  the  lentils. 
Various  beverages  and  condiments  have  no  great  nutri- 
tive value  but  serve  to  stimulate  the  appetite  and  to 
excite  the  secretion  of  the  digestive  juices.  Coffee,  tea, 
and  alcohol  are  stimulants. 

The  different  classes  of  foods  have  different  functions 
in  the  nourishment  of  the  body.  The  proteins  are  pri- 
marily tissue-builders  and  also  help  somewhat  in  force 
production.  The  fats  are  essentially  heat-producers, 
though  they  too  help  in  force-production.  The  carbo- 
hydrates are  chiefly  important  as  force-producers, 
though  they  also  produce  heat  and  to  a  certain  extent 
save  protein  oxidation.  Fat  is  formed  by  all  three  but 


148  THE    ABDOMEN. 

only  in  small  amount  by  proteins.  So  no  one  food  can 
form  the  whole  diet  but  there  must  be.  variety.  Carbo- 
hydrates and  fats  are  not  sufficient  for  life,  some  protein 
is  necessary.  Carbohydrates  are  more  digestible  than 
fats  but  have  less  potential  energy.  Gelatine  saves  waste 
of  nitrogen,  though  it  does  not  increase  the  supply. 
Water  and  salts  are  not  nutritive  but  they  aid  the  body 
processes,  the  water  helping  to  dilute  and  dissolve 
substances  for  digestion. 

The  end-product  of  the  consumption  of  protein  is 
urea,  which  is  eliminated  by  the  kidneys.  Just  where  it 
is  formed  is  unknown,  but  many  think  in  the  liver.  A 
trifling  amount  of  urea  is  also  eliminated  in  the  sweat  and 
in  the  breath  as  well  as  in  the  feces.  Proteins  increase 
nitrogenous  metabolism  and  also  the  metabolism  of 
other  foods,  but  the  amount  of  nitrogen  eliminated  is  just 
equal  to  that  taken  in.  Probably  some  comes  from  the 
tissues  themselves  and  not  from  the  food.  The  oxida- 
tion of  carbohydrates  and  fats  is  measured  by  the  amount 
of  carbon  excreted.  At  first  as  much  is  given  off  as  is 
taken  in,  but  after  a  while  the  carbohydrate  is  stored  up 
as  glycogen  in  the  liver  and  the  fats  are  stored  as  fat. 

The  amount  of  food  needed  varies  with  the  person's 
size  and  occupation,  less  being  needed  for  a  child  than  for 
an  adult  and  more  for  a  hard-working  man  than  for  one 
who  is  doing  less  work.  In  general,  100  to  130  grams  of 
protein,  40  to  80  grams  of  fat,  450  to  550  grams  of  carbo- 
hydrates, 30  grams  of  salts,  and  28,000  grams  of  water 
is  a  fair  amount. 

Foods  are  cooked  to  make  them  more  digestible  and  to 
develop  their  flavor,  so  that  they  will  taste  better.  Cook- 
ing also  kills  germs  and  parasites  that  might  be  harmful. 
Meats  should  be  cooked  rapidly  on  the  outside  to  coagu- 
late the  surface  albumen  and  keep  in  the  juices.  The 
heat,  besides  coagulating  the  albumen,  turns  the  tough 
parts  to  gelatine.  In  cereals  the  tough  envelope  of 
cellulose  is  broken  up  and  in  vegetables  the  tough  fibrous 
parts  are  softened  and  made  more  digestible. 


THE    ABDOMEN.  149 

The  Liver. — Below  the  diaphragm  on  the  right  and 
extending  across  above  the  stomach,  resting  in  a  way 
upon  the  transverse  colon  and  the  small  intestine,  is  the 
liver,  the  largest  gland  in  the  body.  It  is  dark  reddish- 
brown  in  color  and  is  larger  in  proportion  in  the  child  than 
in  the  adult.  The  upper  surface  is  convex  and  lies  in 
contact  with  the  diaphragm,  while  the  lower  surface  is 
concave  to  fit  over  the  organs  beneath.  With  a  full 


FIG.  56. — The   liver,   seen  from  below.     1,  Inferior  vena  cava;  2,  gall-bladder. 

(Morrow.) 

breath  it  comes  downward  and  forward,  with  the  edge 
against  the  abdominal  wall,  and  can  be  easily  felt. 
Numerous  strong  ligaments,  including  the  suspensory 
ligament  from  the  diaphragm,  hold  it  in  place,  and  it  is 
more  firmly  fixed  than  any  other  of  the  abdominal  organs, 
probably  on  account  of  its  large  size.  It  is  divided  by 
fissures  into  five  lobes,  of  which  the  most  important  are 
the  right  and  left,  the  right  one  being  the  largest  and  con- 
taining the  gall-bladder  in  one  of  its  fissures. 

The  liver  tissue  contains  a  large  number  of  cells  collected 


150  THE    ABDOMEN. 

into  lobules,  in  the  center  of  each  of  which  is  a  blood- 
vessel, the  intralobular  vein,  from  which  a  network  of 
capillaries  extends  to  the  edge  of  the  lobule,  there  being 
a  capillary  on  either  side  of  each  row  of  cells.  Between 
the  cells  also  are  the  intercellular  biliary  passages,  roots  of 
the  bile  ducts  which  exist  in  the  connective  tissue  between 
the  lobules  and  which  join  to  form  two  main  ducts,  one 
from  the  right  and  the  other  from  the  left  lobe.  By  the 
union  of  these  two  ducts  the  hepatic  duct  is  formed,  which, 
after  a  course  of  one  or  two  inches,  joins  the  cystic  duct 
from  the  gall-bladder  to  form  the  ductus  communis  or 
common  bile  duct. 

The  liver  has  a  double  blood  supply,  the  hepatic  artery 
from  the  celiac  axis  bringing  nourishment  to  the  connect- 
ive tissue  and  the  walls  of  the  blood-vessels,  while  the 
capillaries  between  the  cells  come  from  the  portal  vein, 
which,  being  formed  by  the  junction  of  the  superior  and 
inferior  mesenteric,  the  splenic  and  the  gastric  veins, 
contains  the  proteins  and  carbohydrates  absorbed  during 
digestion.  After  its  passage  through  the  liver  this  blood 
from  the  portal  vein  is  collected  once  more  into  the 
hepatic  veins,  which  convey  it  to  the  inferior  vena  cava. 
During  its  passage,  however,  various  changes  take  place, 
for  the  liver  plays  an  important  part  in  the  metabolic 
processes  of  the  body. 

The  liver  has  two  principal  functions,  the  secreting  of 
bile  and  the  storing  up  of  glycogen.  The  secretion  of 
bile,  which  is  a  very  important  aid  to  digestion,  is  prob- 
ably a  reflex  act,  the  presence  of  peptones  in  the  portal 
blood  after  meals  acting  as  a  stimulant  to  the  liver  cells. 
For  food  at  once  increases  the  secretion  of  bile,  which  is 
poured  from  the  cells  into  the  small  bile  ducts  and  finally 
passes  into  the  hepatic  duct  and  so  to  the  gall-bladder, 
where  it  is  stored  until  needed.  Although  the  flow  from 
the  liver  is  constant,  the  .amount  secreted  reaches  its 
maximum  when  the  food  gets  down  into  the  small  in- 
testine, that  is,  four  or  five  hours  after  eating,  there  being 
a  lull  before  that.  Apart  from  the  process  of  secretion, 


THE    ABDOMEN.  151 

the  manufacture  of  the  bile  pigments,  bilirubin  and  bili- 
verdin,  which  are  made  from  the  hemoglobin  of  the 
blood,  seems  to  require  some  special  action  on  the  part  of 
the  liver  cells. 

The  glycogen,  which  is  manufactured  and  stored  in  the 
liver  cells,  is  a  clear  hyaline  substance,  akin  to  starch  and 
capable  of  being  converted  into  sugar  by  the  starch  fer- 
ment. Probably  there  is  some  such  ferment  in  the  blood 
which  converts  the  glycogen  into  sugar  as  soon  as  it  passes 
from  the  liver  into  the  blood,  though  what  it  is,  is  not 
known.  Neither  is  it  known  just  how  glycogen  is  formed, 
but  it  is  manufactured  chiefly  after  a  mixed  meal  in  which 
carbohydrates  predominate,  proteins  having  little  and 
fats  no  effect  upon  its  formation.  It  is  undoubtedly 
formed  from  the  sugar  in  the  portal  blood  and  the  pro- 
cess requires  some  work  on  the  part  of  the  liver  cell  itself. 
Probably  there  is  always  some  sugar  in  the  circulating 
blood  which,  as  it  is  used  up,  must  be  made  good.  If 
there  it  not  enough  in  the  diet,  the  liver  supplies  the 
deficiency  from  its  store  of  glycogen. 

Glycogen  is  found  also  in  the  muscles,  in  the  placenta 
as  food  for  the  fetus,  in  leucocytes,  and  to  a  slight  extent 
in  cartilage.  In  fact,  it  is  the  form  in  which  carbohydrate 
material  is  supplied  to  the  tissues  as  needed.  Normally, 
much  of  the  sugar  is  used  up  by  the  blood  and  its  cells  in 
metabolism,  giving  rise  to  heat  and  energy.  In  muscles 
glycogen  is  probably  digested  as  lactic  acid,  as  before 
action  muscle  is  neutral  or  slightly  alkaline  and  after 
action  acid. 

When  the  liver  is  deranged  and  allows  the  glycogen  to 
pass  out  into  the  blood  too  freely,  or  when  the  glycogen  is 
not  held  as  such  but  turned  to  sugar  and  passed  out  in 
large  quantities,  sugar  in  the  urine  or  diabetes  mellitus 
results. 

Besides  its  secreting  function  the  liver  has  an  elimina- 
tive  function  and  plays  an  important  part  in  purifying  the 
blood,  removing  from  it  many  poisonous  and  narcotic 
substances.  It  is  thought  by  some,  though  it  has  not 


152  THE    ABDOMEN. 

been  proved,  that  urea,  the  end-product  of  protein 
metabolism,  which  is  brought  by  the  blood  to  the  kidneys 
and  there  excreted,  is  formed  in  the  liver.  At  any  rate, 
urea  is  formed  not  only  from  the  nitrogenous  food  eaten 
but  from  the  metabolism  of  protein  substances  in  the 
tissues,  being  purely  a  waste  product,  from  which  the 
nutritious  substances  have  been  absorbed.  The  amount 
thrown  off  is  an  accurate  gauge  of  the  amount  of  protein 
metabolism  going  on.  The  process  of  its  manufacture 
is  doubtless  very  complex. 

Ptosis  or  dropping  of  the  liver  sometimes  occurs  and  is 
due  to  the  stretching  of  the  ligaments.  Rupture  is 
common,  generally  as  the  result  of  a  fall  from  a  height, 
on  account  of  its  size  and  friability.  The  liver  is  also 
subject  to  many  diseases.  Cirrhosis  occurs  in  people 
who  drink  a  good  deal  and  in  its  later  stages  is  accom- 
panied by  ascites,  an  accumulation  of  fluid  in  the  ab- 
dominal cavity.  When  there  is  a  general  accumulation  of 
fluid  throughout  the  body  it  is  known  as  anasarca. 
Syphilis  causes  enlargement  of  the  liver.  Abscesses 
occur,  perhaps  oftener  in  the  tropics  than  farther 
north,  and  may  break  into  the  lungs,  stomach,  or 
intestine. 

The  Gall-bladder. — The  gall-bladder,  which  is  simply 
a  reservoir  for  the  bile,  is  a  pear-shaped  organ  three  inches 
long  and  one  inch  broad.  It  lies  in  a  fossa  on  the  under 
side  of  the  liver,  with  the  large  end  or  fundus  touching 
the  abdominal  wall  just  below  the  ninth  costal  cartilage. 
Here  it  can  be  felt  as  a  small  mass  in  empyema  of  the 
gall-bladder.  Normally  it  holds  a  little  over  one  ounce, 
but  with  occlusion  it  may  become  stretched.  Its  duct 
is  the  cystic  duct,  which  joins  the  hepatic  duct  in  the 
common  bile  duct,  but  bile  only  passes  up  into  the  gall- 
bladder when  the  opening  into  the  duodenum  is  closed, 
that  is,  between  meals. 

If  one  of  the  bile  ducts  is  stopped  up  by  a  stone  or 
cancer  or  for  any  other  cause,  the  bile  backs  up  in  the 
liver,  the  pigments  are  absorbed  into  the  circulation, 


THE    ABDOMEN. 


153 


and  jaundice  results.  In  this  condition  operation  is 
dangerous,  as  the  time  of  coagulation  of  the  blood,  nor- 
mally five  minutes  or  less,  is  much  delayed.  Gall-stones, 
formed  largely  of  bile  pigments  and  cholesterin,  some- 
times collect  in  the  gall-bladder,  where  they  cause  irrita- 
tion and  may  give  rise  to  empyema  of  the  gall-bladder. 
The  stones  vary  in  size  from  a  pea  to  a  hen's  egg  and 
when  small  may  be  very  numerous. 

The   Pancreas. — Another    accessory    organ    of    diges- 
tion is  the  pancreas,  the  abdominal  salivary  gland,  as 


Head  of  Tc 


FIG.  57. — The  pancreas,  spleen,    gall-bladder,  etc.,  showing  their  relations. 
(After  Sobotta.) 

it  is  sometimes  called  on  account  of  its  close  resem- 
blance to  the  parotid  gland.  This  is  a  grayish-white 
racemose  gland,  six  and  a  half  inches  long  by  one  and 
a  half  inches  wide  and  one  inch  thick,  lying  behind 
the  stomach  on  a  level  with  the  first  and  second  lumbar 
vertebrae  and  shaped  like  a  pistol  with  its  handle  toward 
the  right.  In  an  emaciated  person  it  can  be  felt.  The 


154  THE    ABDOMEN. 

pancreatic  duct  runs  the  whole  length  of  the  gland  from 
left  to  right  and  conveys  the  pancreatic  juice  from  vari- 
ous little  glands  in  the  substance  of  the  organ  to  the 
duodenum,  into  which  it  empties  along  with  the  com- 
mon bile  duct  by  a  common  orifice.  The  arteries  are 
from  the  celiac  axis  and  superior  mesenteric,  the  veins 
belong  to  the  portal  system,  and  the  nerves  come  from 
the  solar  plexus. 

Surgically  the  pancreas  is  of  no  special  importance, 
though  acute  pancreatitis  does  occasionally  occur  and 
is  a  very  serious  condition  and  one  hard  to  diagnose. 

The  Spleen. — The  largest  and  most  important  of 
the  ductless  glands  is  the  spleen,  an  oblong,  flattened 
organ  lying  deep  in  the  left  hypochondriac  region  be- 
tween the  stomach  and  diaphragm  above  the  descend- 
ing colon,  and  corresponding  to  the  ninth,  tenth,  and 
eleventh  ribs.  It  is  soft,  brittle,  and  very  vascular.  Its 
artery  is  a  branch  of  the  celiac  axis  and  the  vein  belongs 
to  the  portal  system.  Its  nerves  are  the  pneumogas- 
tric  and  branches  from  the  solar  plexus.  The  function 
is  not  well  understood  but  probably  it  is  connected 
with  or  related  to  the  vascular  system  in  some  way. 
Perhaps  it  manufactures  blood  corpuscles. 

The  spleen  varies  more  in  size  than  any  other  organ. 
Normally  it  cannot  be  felt,  but  in  typhoid  it  usually 
can.  It  is  generally  atrophied  in  old  age  and  hyper- 
trophied  in  almost  all  acute  infectious  diseases,  especi- 
ally in  typhoid  fever  and  malaria.  In  leukemia  it  is 
often  greatly  enlarged.  Sometimes  in  violent  falls  it 
is  ruptured  and  there  is  considerable  hemorrhage. 

The  Suprarenal  Capsules. — The  other  ductless  glands, 
the  suprarenal  capsules,  yellowish  triangular  bodies, 
are  situated  just  above  and  in  front  of  the  kidneys. 
Their  function  is  important  but  not  well  understood. 
Death,  accompanied  by  great  muscular  weakness,  follows 
the  removal  of  both,  and  when  they  are  diseased,  similar 
weakness  is  observed  and  the  skin  becomes  bronzed. 
Injection  of  the  extract  of  the  suprarenals  stimulates 


THE    ABDOMEN. 


155 


the  muscular  system.  So  probably  they  secrete  into  the 
blood  minute  quantities  of  a  substance  or  substances 
beneficial  to  the  body,  especially  to  the  muscular  system. 
The  Kidneys. — The  two  kidneys  lie  on  either  side  of 
the  vertebrae  at  the  back  of  the  abdominal  cavity  and 
behind  the  peritoneum,  between  the  last  dorsal  and 
the  third  lumbar  vertebrae,  their  inner  edge  being  about 
one  inch  from  the  spinous  processes.  They  are  bean- 
shaped,  four  inches  long,  two  inches  wide,  and  one  inch 


FIG.  58. — Diagram  of  the  relation  of  kidney  to  viscera,  spine,  and  surface 
points.     (American  Text- Book  of  Surgery.) 

thick,  and  are  embedded  in  a  mass  of  fat  and  loose  areolar 
tissue.  They  can  be  felt  only  when  misplaced  or  when 
enlarged,  as  by  tuberculosis  or  malignant  disease. 

The  whole  kidney  is  enveloped  in  a  fibrous  capsule 
which  normally  may  be  peeled  off  but  which  in  some 
diseases  becomes  adherent.  On  the  internal  border  is 
a  fissure  or  hilum,  through  which  pass  the  blood  ves- 
sels and  the  ureter.  Upon  entering,  the  ureter  dilates 
into  a  sac,  the  pelvis  of  the  kidney,  into  which  project 
the  Malpighian  pyramids  of  the  medullary  substancef 
a  substance  made  up  of  the  straight  uriniferous  tubules 


156 


THE    ABDOMEN. 


and  blood-vessels.  Outside  the  medullary  substance 
and  just  under  the  capsule  is  the  cortex,  containing 
the  Malpighian  bodies,  blood-vessels,  and  the  con- 
voluted tubules  or  loops  of  Henle.  Each  Malpighian 
body  contains  within  a  capsule  a  plexus  of  capillaries, 
the  glomerulus}  with  an  afferent  arteriole  and  an  effer- 
ent vein.  The  renal  artery  is  a  branch  of  the  aorta  and 
the  nerves  are  from  the  solar  plexus. 


Fie.  59. — A  longitudinal  section  of  FIG.  60. — A  Malpighian  body  or 

the  kidney.       (Leroy.)     a,  Renal  ar-        corpuscle.      (Leidy.)     a,  Afferent 
tery;  c,  cortex;  TO,  medulla;  u,  ureter.         artery;  e,  efferent  vessel;  c,  capil- 
laries; k,  commencement  of  urinif- 
erous  tubule;  h,  uriniferous  tubule. 

The  Urine. — As  the  blood  passes  through  the  glom- 
eruli,  the  urine  is  filtered  off  as  it  were,  probably  by 
a  process  of  transudation  rather  than  simple  filtration. 
The  cells  lining  the  tubules  also  play  an  important 
part  in  its  formation,  not  by  secreting  new  substances 
but  by  taking  up  those  brought  by  the  blood  and  dis- 
charging them  into  the  convoluted  tubules,  from  which 
the  urine  passes  through  the  straight  tubules  of  the 
medulla  to  the  pelvis,  to  be  carried  thence  by  the  ure- 
ter. The  process  of  the  formation  of  the  urine,  there- 


THE    ABDOMEN.  157 

fore,  is  not  purely  a  process  of  secretion  but  requires 
some  action  on  the  part  of  the  kidney,  though  no  new 
substances  are  secreted  in  the  kidney. 

The  passage  of  the  urine  down  through  the  ureters 
is  assisted  by  a  kind  of  peristaltic  action  in  the  walls 
of  the  ureters  and  it  is  expelled  from  the  body  by  the 
act  of  micturition,  which  is  mostly  voluntary,  though 
a  certain  amount  of  nervous  mechanism  controls  it. 
The  seat  of  this  nervous  mechanism  is  in  the  lum- 
bar enlargement  of  the  spinal  cord.  In  some  nervous 
conditions,  especially  where  there  is  injury  to  the  spinal 
cord,  there  is  involuntary  micturition. 

The  urine  is  a  watery  solution  containing  many  waste 
products,  especially  urea.  It  is  generally  amber  in 
color,  varying  in  shade  with  circumstances,  with  an 
aromatic,  characteristic  odor  when  fresh.  It  is  acid 
in  reaction  and  has  a  specific  gravity  of  about  1020, 
though  this  too  varies  with  circumstances.  Besides 
water,  which  is  its  chief  constituent,  it  contains  urea, 
uric  acid,  organic  acids,  urates,  inorganic  salts,  includ- 
ing sodium  chloride  and  phosphates  of  calcium  and 
magnesium,  a  certain  amount  of  ammonia,  and  certain 
pigments.  Its  acidity  is  due  to  acid  sodium  phosphate 
in  solution  but  varies  with  the  food,  and  in  disease  the 
urine  may  become  alkaline  when  passed.  After  stand- 
ing a  few  hours  in  a  warm  place  it  decomposes  and  be- 
comes alkaline. 

The  quantity,  which  is  normally  three  pints  or  fif- 
teen hundred  cubic  centimeters  in  twenty-four  hours, 
varies  with  the  amount  of  fluid  drunk,  the  amount  of 
perspiration,  etc.  The  amount  secreted  depends  chiefly, 
however,  upon  the  flow  of  the  blood  through  the  kidneys; 
the  greater  the  flow  of  blood,  the  larger  the  amount  of 
urine  formed;  and  the  blood  flow  is  determined  by  blood 
pressure  and  by  vasomotor  action.  Secretion  also  seems 
to  be  increased  by  the  presence  of  urea,  which  apparently 
serves  as  a  stimulant  to  the  kidney  cells. 

The  excretion  of  waste  materials  takes  place  by  three 


158  THE    ABDOMEN. 

main  channels,  the  lungs,  skin,  and  kidneys,  and  the 
materials  are  of  four  kinds,  urea,  carbon  dioxide,  salts, 
and  water.  The  lungs  carry  off  carbon  dioxide  and 
water  chiefly,  the  skin  these  and  inorganic  salts,  while 
the  kidneys  eliminate  practically  all  the  urea  as  well 
as  inorganic  salts  and  water.  When  the  kidneys  are 
not  working  the  skin  carries  off  much  urea.  In  fact, 
a  close  relationship  exists  between  the  kidneys  and  the 
skin  in  the  matter  of  excretion.  Thus,  with  increased 
perspiration  in  warm  weather  comes  decreased  urine, 
while  in  cold  weather  the  blood  is  sent  in  and  the 
urine  increased  in  amount. 

To  incite  action  of  the  kidneys  drugs  known  as 
diuretics  may  be  used.  These  act  in  two  ways,  by  stim- 
ulating the  kidney  cells  directly  and  by  acting  on  the 
general  circulation  or  nervous  system.  Any  emo- 
tional or  nervous  excitement  increases  the  flow  of 
urine. 

There  are  certain  abnormal  constituents  of  urine, 
of  which  the  two  most  important  are  albumen  and 
sugar.  The  former  is  found  only  when  there  is  some 
disturbance  of  the  kidneys,  ureters,  or  bladder,  and  its 
presence  usually  denotes  some  change  in  the  cells  lining 
the  urinary  tract.  It  may  occur  in  congestion  of  the 
kidney  as  well  as  in  disease.  Sugar  is  found  only  in  dia- 
betes, the  amount  varying  with  the  severity  of  the  dis- 
ease. In  jaundice  certain  bile  pigments  are  present  in 
the  urine,  giving  it  a  dark  brown  color  and  to  the  foam 
a  greenish-yellow  color.  Even  normal  urine  has  some 
sediment  upon  standing,  consisting  of  cells  from  the 
urinary  tract  and  mucus.  In  very  acid  urine  after 
standing  a  heavy  sediment,  whitish  or  pinkish,  i.e.,  brick 
dust,  in  color,  is  thrown  down.  It  does  not  necessar- 
ily denote  disease,  but  shows  the  urine  is  acid  and  con- 
centrated. In  alkaline  urine  there  is  a  sediment  due 
to  phosphates. 

Rupture  of  the  kidney  occurs  but  is  not  so  serious  as 
rupture  of  the  liver  or  spleen  because  the  kidney  is  sit- 


THE    ABDOMEN. 


159 


uated  outside  of  the  peritoneum.  It  necessitates  the 
removal  of  the  kidney,  however,  and  when  for  any  rea- 
son one  kidney  is  removed  the  other  increases  in  size 
and  does  double  work  to  compensate  for  the  loss.  Re- 
moval of  both  kidneys  means  death.  Sometimes  the 
kidney  becomes  loose  and  moves  about,  a  condition 
known  as  floating  kidney.  Perinephritic  abscess  is  ab- 
scess in  the  loose  fatty  tissue  about  the  kidney. 

The  Ureters,  one  for  each  kidney,  are  tubes  the  size 
of  a  goose  quill  and  about  fourteen  inches  long,  extend- 
ing from  the  hilum  of  the  kidney  to  the  base  of  the  blad- 


iJnev 


'thro. 
FIG.    61. — The  urinary  organs  viewed  from  behind. 

der.  They  have  three  coats,  an  internal  mucous,  a 
muscular,  and  an  external  fibrous  coat,  this  last  being 
continous  with  the  cortex  of  the  kidney  and  the  fibrous 
tissue  of  the  bladder.  In  the  female  the  ureters  may 
be  felt  through  the  wall  of  the  vagina  as  they  come  into 
the  bladder.  In  tubercular  disease  of  one  kidney  the 
ureter  becomes  inflamed  and  enlarged  and  through  the 
vagina  feels  almost  like  a  lead  pencil,  a  sure  diagnostic 
sign. 

The   Bladder   and  Urethra. — In   their   course   to   the 
bladder  the  ureters  pass  from  the  abdominal  into  the 


160  THE    ABDOMEN. 

pelvic  cavity,  but  before  describing  the  pelvis  itself  it 
will  be  well  to  complete  the  account  of  the  urinary  or- 
gans by  considering  the  bladder  and  urethra.  The 
bladder  is  the  reservoir  for  the  urine  and  has  muscular 
walls  lined  with  mucous  membrane.  A  peritoneal  coat 
covers  the  upper  surface  and  is  reflected  to  the  walls  of 
the  abdomen  and  pelvis.  It  is  situated  back  of  the  os 
pubis,  the  front  bone  of  the  pelvis,  with  its  base  or 
fundus  directed  downward  and  backward.  Normally  it 
is  in  the  pelvis,  but  when  much  distended  it  mounds  up 
into  the  abdominal  cavity,  where  it  can  be  felt  in  front 
as  a  tumor.  It  rests  on  the  rectum  in  the  male  and  on 
the  cervix  in  the  female  and  is  held  in  place  by  numer- 
ous ligaments.  When  empty  it  may  be  Y-shaped,  but 
it  becomes  oval  when  distended.  Its  capacity  is  about 
one  pint. 

The  lower  abdominal  wall  and  the  anterior  wall  of 
the  bladder  may  be  wanting  congenitally.  In  paralysis 
of  the  sphincter  at  the  neck  of  the  bladder  distention 
results.  Stones  may  be  found  in  the  bladder. 

From  the  neck  of  the  bladder  the  urine  passes  out  of 
the  body  through  the  urethra.  This  in  the  male  passes 
down  through  the.  penis  and  is  about  ten  inches  long. 
Except  when  urine  is  passing  it  is  a  transverse  slit  with 
the  upper  and  under  surfaces  in  contact,  while  at  the 
end  of  the  penis  the  slit  of  the  meatus  urinarius  is  vertical. 
When  the  penis  is  flaccid,  the  urethra  describes  a  sharp 
curve  before  its  entrance  into  the  bladder,  but  it  be- 
comes approximately  straight  when  the  penis  is  raised 
at  right  angles  to  the  body — an  important  point  to  re- 
member in  catheterization. 

In  the  female  the  urethra  is  straight  and  much  shorter, 
being  only  about  one  and  a  half  inches  long.  The 
meatus  urinarius  is  in  the  anterior  vaginal  wall  about 
one  inch  behind  the  clitoris. 

Sometimes  the  urethra  is  ruptured  in  a  fall.  Strict- 
ure of  the  urethra  occurs  sometimes  after  gonorrhoea, 
owing  to  the  formation  of  scar  tissue  following  ulcer. 


CHAPTER  XI. 
THE  PELVIS  AND  THE  GENITAL  ORGANS. 

The  Pelvis. — Before  taking  up  the  pelvic  organs,  the 
pelvis  itself  should  be  described.  The  name  pelvis  has 
been  given  to  the  bony  ring  which  is  interposed  between 
the  spine  and  the  femurs  on  account  of  its  resemblance 
to  a  basin.  At  the  back  of  this  basin  or  pelvis  are  the 
sacrum  and  coccyx,  already  described  in  connection  with 


FIG.  62. — Front  view  of  the  pelvis,  with  its  ligaments.  (Borland.)  a,  Anter- 
ior sacro-iliac  ligament;  6,  iliofemoral  ligament;  c,  obturator  membrane ;d,  sym- 
physis  pub  is;  e,  sacroseiatic  ligament. 

the  back,  and  at  the  sides  and  meeting  in  the  median 
line  in  front  are  the  two  ossa  innominata  or  nameless 
bones,  so  called  on  account  of  their  peculiar  and  inde- 
scribable shape.  At  birth  each  os  innominatum  is  made 
up  of  three  bones,  the  ilium,  ischium,  and  pubes,  but 
about  the  age  of  puberty  the  three  become  welded  into 
11  161 


162 


THE    PELVIS    AND    THE    GENITAL    ORGANS. 


one.  At  their  point  of  junction  is  the  cavity  of  the 
acetabulum  for  articulation  with  the  head  of  the  femur 
or  thigh  bone. 

The  upper,  expanded  portion  of  the  os  innominatum 
is  the  ilium,  whose  upper  border  is  known  as  the  crest 
and  which  has  two  spinous  processes  front  and  back,  a 
superior  and  an  inferior,  the  superior  spine  being  in  each 

Crest  of  ilium. 


Anterior  gluteal  line. 

Ala  of  ilium.  ^ .J^^jjjj  jj|!j  |i  ?,y      •&£?     "-  Anterior  superior  spine. 

ill 

Iliac  portion. 


Semilunar 

surface. 


Acetabular  fossa 

Cotyloid  notch.  - 
Ischiatic  portion. 

Tuberosity  of  ischium.  — 


-"  Iliopectineal  eminence. 


Pubic  portion. 


-Spine  of  pubes. 


\ 


Ramus  of  pubes. 


Obturator  foramen.  Ramus  of  ischium. 

FIG.  63.— The  right  innominate  bone.  (After  Toldt.) 

case  the  larger.  These  spines,  especially  the  anterior 
superior  spines,  and  the  crest  give  attachment  to  many 
muscles,  and  to  the  outer  surface  of  the  bone  the  glu- 
teal muscles  are  attached.  The  anterior  superior  spine 
is  also  important  in  making  measurements  to  ascer- 
tain whether  both  legs  are  of  equal  length. 

Below  the  ilium  posteriorly  is  the  body  of  the  isch- 


THE    PELVIS    AND    THE    GENITAL    ORGANS.  163 

ium,  which  has  on  its  lower  edge  a  tuberosity,  the  promi- 
nent bone  on  which  one  sits.  Near  the  upper  edge 
is  the  spine  of  the  ischium,  between  which  and  the  pos- 
terior inferior  spine  of  the  ilium  is  the  greater  sacro-sciatic 
notch  for  the  passage  of  vessels  and  nerves,  including 
the  sciatic  nerves.  From  the  tuberosity  the  ramus  ex- 
tends forward  below  the  obturator  foramen,  a  large  open- 
ing between  the  ischium  and  the  pubes,  also  for  the 
passage  of  vessels  and  nerves,  to  meet  the  pubes,  the 
last  and  smallest  of  the  three  bones  which  go  to  make 
up  the  os  innominatum. 

The  anterior  surface  of  each  pubes  presents  a  crest, 
ending  externally  in  a  spine,  and  the  two  pubic  bones 
join  in  front  in  the  symphysis  pubis.  The  bone  gets 
its  name  from  the  growth  of  pubic  hairs  over  this  region 
at  puberty. 


FIG.  64.— Diameters  of  the  pelvis:  d,  antero-pos tenor;  ob,  oblique; 
t  r,  transverse,     (de  Nancrede.) ' 

Anteriorly  the  ossa  innominata  support  the  external 
organs  of  generation,  while  within  are  the  internal  or- 
gans of  generation.  On  the  inner  surface  of  the  ilium, 
slightly  above  the  level  of  the  acetabulum,  is  the  ileo- 
pectineal  line,  above  which  lie  the  iliac  fossce.  A  plane 
drawn  through  the  prominence  of  the  sacrum,  the  ileo- 
pectineal  lines,  and  the  upper  margin  of  the  symphysis 
pubis  serves  to  divide  the  upper  or  false  pelvis  from 
the  lower  or  true  pelvis.  The  false  pelvis,  which  is 
the  larger,  serves  to  support  the  intestines  and  to 


164     THE  PELVIS  AND  THE  GENITAL  ORGANS. 

take  part  of  the  weight  from  the  abdominal  walls, 
while  the  true  pelvis,  being  more  surrounded  by 
bone  and  so  capable  of  affording  more  protection, 
guards  the  internal  organs  of  generation.  The  lower 
circumference  of  the  pelvis  is  known  as  the  outlet.  In 
the  female  the  bones  are  lighter,  the  sacrum  less  curved, 
and  the  diameters  greater  than  in  the  male. 

On  the  whole,  the  pelvic  bones  are  well  covered  in  with 
muscles.  The  anterior  superior  spine,  however,  is  easily 
felt  in  front  and  the  whole  crest  can  be  felt  back  to  the 
posterior  superior  spine.  The  tuberosity  of  the  ischium 
also  can  be  felt,  especially  when  the  thigh  is  flexed, 
for  it  is  largely  uncovered  of  muscles.  The  spine  of 
the  os  pubis  can  always  be  felt,  on  a  level  with  the  great 
trochanter,  and  the  relation  of  its  position  to  that  of 
a  hernia  shows  whether  the  rupture  is  above  or  below 
Poupart's  ligament,  that  is,  whether  it  is  inguinal  or 
femoral. 

Occasionally  there  is  lack  of  development  of  the  pubic 
bones  for  two  or  three  inches  and  the  bladder  is  exposed. 
Fracture  of  the  pelvis  may  occur,  perhaps  with  injury 
to  the  viscera.  The  acetabulum  may  be  fractured 
or  the  sacrum  broken,  with  injury  to  the  sacral  plexus 
of  nerves,  causing  paralysis  of  the  lower  extremities 
and  of  the  sphincters,  with  resultant  involuntary  pas- 
sage of  urine  and  feces,  and  in  childbirth  the  coccyx 
is  often  broken.  In  rickets  there  may  be  great  deform- 
ity of  the  pelvis,  causing  trouble  in  childbirth  later  in 
life.  Osteomalacia  is  a  disease  of  adults,  in  which  the 
bones  are  soft  and  the  weight  pushes  the  promontory 
of  the  sacrum  forward  and  approximates  the  sides  of 
the  pelvis. 

The  Male  Generative  Organs. — The  male  generative 
organs  consist  of  the  prostate  gland,  testes,  and  penis. 

The  prostate  gland  is  shaped  like  a  small  horse-chest- 
nut and  is  composed  of  numerous  glands  from  which 
come  a  dozen  or  more  excretory  ducts.  It  surrounds 
the  neck  of  the  bladder  and  the  beginning  of  the  urethra 


THE    PELVIS    AND   THE_GENITAL    ORGANS.  165 

and  is  next  to  the  rectum,  through  which  an  examina- 
tion may  be  made  to  determine  its  size.  For  it 
often  enlarges  in  elderly  men,  the  frequent  passage  of 
urine  in  small  amounts  being  a  symptom  of  enlarged 
prostate. 

The  procreating  glands,  which  secrete  the  spermatozoa 
or  semen,  are  two  in  number,  the  testes  or  testicles,  and 
are  homologous  to  the  ovaries  in  the  female.  They  are 
ovoid  in  form  and  are  suspended  by  the  spermatic  cords 
in  a  sac,  the  scrotum,  back  of  the  penis.  During  early 
fetal  life  they  are  in  the  back  of  the  abdomen  near  the 
kidneys,  but  before  birth  they  descend  along  the  in- 
guinal canals  into  the  scrotum.  The  excretory  duct 
of  the  testis  is  called  the  vas  deferens.  It  passes  up  by 
the  spermatic  cord  through  the  inguinal  canal  into  the 
pelvis  to  the  base  of  the  bladder  and  at  the  base  of  the 
prostate  joins  the  duct  of  the  vesicula  seminalis  to 
form  the  ejaculatory  duct.  The  two  vesiculce  seminales 
are  small  receptacles  for  the  semen  lying  in  contact  with 
the  base  of  the  bladder  and  secrete  a  fluid  with  which 
they  dilute  the  semen.  The  ejaculatory  duct  terminates 
near  the  prostate  in  the  urethra  by  a  slit-like  orifice  on 
each  side,  the  spermatozoa  being  finally  excreted  through 
the  urethra. 

The  penis  is  the  external  organ  of  generation  in  the 
male  and  is  attached  to  the  pubes  and  the  anterior  part 
of  the  ischium.  It  is  composed  of  erectile  tissue  and 
encloses  the  urethra,  the  meatus  urinarius  appearing 
at  its  end  as  a  vertical  slit.  Toward  the  end  the  skin 
of  the  penis  is  loose  and  is  prolonged  forward  in  what 
is  known  as  the  prepuce  or  foreskin.  It  is  this  that  is 
clipped  away  in  circumcision. 

The  Female  Generative  Organs. — The  female  genera- 
tive organs  include  the  ovaries,  Fallopian  tubes,  uterus, 
vagina,  and  the  external  genitalia  or  vulva. 

The  ovaries,  which  are  homologous  to  the  testes  in 
the  male,  are  two  flattened  oval  bodies,  grayish  pink 
in  color,  suspended  from  the  lateral  or  broad  ligaments 


166     THE  PELVIS  AND  THE  GENITAL  ORGANS. 

which  fasten  the  uterus  to  the  walls  of  the  pelvis.  They 
are  one  and  a  quarter  inches  long,  three  quarters  of 
an  inch  wide,  and  half  an  inch  thick  and  are  attached  at 
the  upper  end  to  one  of  the  fimbrise  of  the  Fallopian 
tubes.  They  consist  of  numerous  Graafian  follicles  em- 
bedded in  a  fibrous  stroma,  each  follicle  containing  an 
ovum  about  TJT  inch  in  diameter  and  just  visible  to  the 
naked  eye.  When  a  follicle  ruptures  and  discharges  an 


FIG.  65. — View  of  the  pelvis  and  its  organs.  (Savage.)  B,  Bladder;  U,  uterus 
(drawn  down  by  loop  e);  F,  Fallopian  tubes;  O,  ovaries;  L,  round  ligaments; 
g,  ureter;  a,  ovarian  vessels,  often  prominent  under  their  peritoneal  covering;  R, 
rectum;  V,  vertebra. 

ovum,  an  irregular  yellow  spot,  the  corpus  luteum,  ap- 
pears at  the  point  of  rupture.  After  ordinary  menstru- 
ation it  is  known  as  the  false  corpus  luteum  and  after 
conception  as  thejrue  one,  this  one  being  larger  and  last- 
ing longer. 

The  Fallopian  tubes  are  the  oviducts  and  convey 
the  ova  from  the  ovaries  to  the  uterus.  They  are  four 
inches  long  and  lie  between  the  layers  of  the  broad 
ligaments,  opening  into  the  uterus  by  an  orifice  the 
size  of  a  bristle,  while  the  end  next  to  the  ovary  spreads 


THE    PELVIS    AND    THE    GENITAL    ORGANS. 


167 


out  trumpet-like  and  is  edged  with  fimbrioe  as  with  a 
fringe,  the  fimbriated  extremity.  There  are  three 
coats:  a  serous  coat  which  is  continuous  with  the  perito- 
neum, a  muscular  coat,  and,  within,  a  mucous  coat 
covered  with  cilia,  continuous  with  the  mucous  mem- 
brane of  the  uterus.  One  fimbria  is  attached  to  the 


FIG.  66. — Sagittal  section  of  the  female  pelvis.     (Dickinson.) 

ovary  and  as  the  ovum  is  given  off  it  finds  its  way  into 
the  tube  and  thence  to  the  uterus. 

The  uterus  is  a  pear-shaped  organ,  about  three  inches 
long,  two  inches  broad  above,  and  one  inch  thick,  situated 
in  the  pelvic  cavity  between  the  rectum  and  the  bladder. 
The  wide  part  or  fundus  is  above  and  the  narrow 


168     THE  PELVIS  AND  THE  GENITAL  ORGANS. 

neck  or  cervix  below,  lying  partly  within  the  vagina. 
The  whole  is  held  in  place  by  ligaments.  These  in- 
clude the  broad  ligaments,  which  extend  from  the  sides  of 
the  uterus  to  the  lateral  walls  of  the  pelvis,  and  the 
round  ligaments,  two  muscular  cords,  about  four  inches 
long,  which  pass  out  through  the  abdominal  ring  into 
the  inguinal  canal  and  so  to  the  mons  veneris  and  labia, 
thus  corresponding  to  the  spermatic  cords  in  the  male. 
The  cavity  of  the  body  of  the  uterus  is  small  and 
flattened  and  opens  into  the  cervix  by  the  internal  os 
uteri,  the  external  os  being  at  the  opening  of  the  cervix 
into  the  vagina.  There  are  three  coats:  a  serous  coat 
derived  from  the  peritoneum,  a  muscular  coat  of  un- 
striped  fibers  which  forms  the  bulk  of  the  whole  organ, 
and  a  mucous  coat  covered  with  ciliated  epithelium. 

The  uterus  is  always  enlarged  during  menstruation 
and  is  enormously  enlarged  in  pregnancy.  It  receives 
the  fecundated  ovum,  retains  and  supports  it  during 
the  development  of  the  fetus,  and  is  the  chief  agent  of 
expulsion.  In  tubal  or  extra-uterine  pregnancy  the  ovum 
becomes  attached  in  the  tube  instead  of  in  the  uterus, 
and  develops  there,  rupturing  the  tube  and  causing 
serious  hemorrhage. 

The  passage  from  the  cervix  out  of  the  body  is  the 
vagina,  a  membranous  canal,  curved  upward  and  back- 
ward to  conform  to  the  axis  of  the  pelvis,  and  attached 
above  to  the  cervix.  Ordinarily  the  sides  are  in  con- 
tact. 

The  arteries  of  the  internal  organs  of  generation  are 
the  uterine  from  the  internal  iliac  and  the  ovarian  from 
the  aorta  in  the  female,  the  pudic  branches  of  the  in- 
ternal iliac  and  the  spermatic  from  the  aorta  in  the 
male.  The  nerves  are  largely  from  the  sympathetic 
system. 

Abscess  formation  occurs  frequently  in  the  tubes  and 
gonorrheal  infection  may  spread  up  the  vagina  and 
through  the  uterus  to  the  tubes,  and  even  to  the  ab- 
dominal cavity  itself,  The  tubes  may  also  be  tubercular, 


THE    PELVIS    AND    THE    GENITAL    ORGANS. 


169 


Salpingectomy  or  removal  of  the  tubes  is  the  commonest 
operation  after  that  for  appendicitis.  Cancer  of  the 
uterus  may  necessitate  panhystercctomy  or  removal  of 
the  uterus  and  all  its  appendages. 

The  external  genitalia  in  the  female,  as  in  the  male, 
are  situated  over  the  pubic  arch.     They  are  known  as 


FIG.  67. — Virginal  vulva.  (Modified  from  Tarnief.)  1,  labia  majora;  2, 
fourchet;  3,  labia  minora;  4,  glans  clitoridis;  5,  meatus  urinarius;  6,  vestibule;  7. 
entrance  to  the  vagina;  8,  hymen;  9,  orifice  of  Bartholin's  gland;  10,  anterior 
commissure  of  labia  majora;  11,  anus;  12,  blind  recess;  13,  fossa  navicularis; 
14,  body  of  clitoris. 

the  vulva  and  include  the  mons  Veneris,  the  labia  ma- 
jora and  minora,  the  vaginal  orifice,  the  clitoris,  and  the 
meatus  urinarius. 

The  mons  Veneris  is  a  rounded  eminence  composed 
of  fatty  tissue,  which  surmounts  the  pubic  bones  and 
is  covered  with  hair  at  puberty.  From  it  two  promi- 
nent longitudinal  folds  of  skin,  covered  with  hair  on 
the  outside,  the  labia  majora,  extend  backward,  form- 


170     THE  PELVIS  AND  THE  GENITAL  ORGANS. 

ing  the  lateral  boundaries  of  the  vulva.  Within  these 
labia  again  are  two  thin  cutaneous  folds,  the  labia  minora 
or  nymph(K,  which  run  back  from  the  clitoris  for  about 
one  and  a  half  inches  and  enclose  the  vaginal  orifice. 
The  clitoris  corresponds  to  the  penis  and  is  just  above 
the  upper  part  of  the  labia  minora.  Between  it  and  the 
vagina  is  the  meatus  urinarius.  The  orifice  of  the  vagina 
is  partly  closed  in  the  virgin  by  the  hymen,  a  thin  fold  of 
mucous  membrane,  which  occasionally  closes  it  com- 
pletely, imperforate  hymen.  The  fourchette  is  a  small  trans- 
verse fold  of  skin  at  the  junction  of  the  labia  minora 
posteriorly.  Between  the  vagina  and  the  rectum  is  the 
perineal  body,  a  somewhat  triangular  structure  made  up 
of  many  small  muscles.  Its  surface  is  known  as  the  peri- 
neum. It  is  frequently  torn  wholly  or  in  part  during 
childbirth  and  has  to  be  sewed  up. 


CHAPTER  XII. 
THE  UPPER  EXTREMITIES. 

The  upper  extremities  include  the  shoulders,  arms, 
forearms,  wrists,  and  hands  and  contain  each  thirty- 
two  bones.  The  bones  of  the  two  shoulders  taken  to- 
gether are  called  the  shoulder  girdle  and  consist  of  the 
two  clavicles  or  collar  bones  and  the  two  scapulae  or  shoul- 
der blades,  which  together  make  an  almost  complete 
girdle  of  the  shoulders. 

The  clavicle  is  a  long  slender  bone  extending  almost 
horizontally  from  the  sternum  to  the  scapula  and  can 
be  felt  for  its  whole  length  in  the  living.  For  the  inner 
two-thirds  it  is  convex  anteriorly,  for  the  outer  third 
concave.  In  woman  it  is  generally  less  curved,  smoother, 
and  more  slender  than  in  man,  and  as  bone  is  rough 
when  the  muscles  attached  are  powerful,  the  right  clav- 
icle, being  used  more,  is  generally  rougher  and  thicker 
than  the  left.  Among  the  muscles  attached  are  the 
large  neck  muscle,  the  sterno-cleido-mastoid,  whose 
tendons  form  the  presternal  notch,  the  trapezius,  the 
pectoralis  major,  and  the  deltoid. 

Being  slender  and  superficial  the  clavicle  is  most 
frequently  broken  of  any  bone  in  the  body,  generally 
by  indirect  violence,  as  by  falling  with  the  hand  out, 
though  old  people  in  such  a  case  are  apt  to  get  Colles' 
fracture  at  the  wrist.  The  bone  generally  gives  way 
at  the  juncture  of  the  outer  and  middle  thirds,  with 
displacement  of  the  parts  inward,  so  that  the  fracture 
is  seldom  compound.  Since,  however,  the  main  ves- 
sels of  the  upper  arm,  with  their  nerves,  lie  beneath  the 
clavicle,  there  is  danger  of  their  being  punctured.  Such 
serious  injury  is  guarded  against  by  the  presence  of 

171 


172 


THE   TIPPER    EXTREMITIES. 


Humerus- 


Radius. 
Interosseous  space.. 


Scapula. 


Pronator  quadratus. 


Carpus. 
Metacarpus. 

^".~5?  Phalanges. 


FIG.  68.— Bones  of  the  upper  extremity.     (Toldt.) 


THE    UPPER    EXTREMITIES. 


173 


the  subclavius  muscle.     The  clavicle  is  occasionally  re- 
moved for  sarcoma. 

The  scapula  or  shoulder  blade,  so  called  from  its  shape, 
is  a  large,  flat,  triangular  bone  with  a  prominent  ridge, 
the  spine,  crossing  its  dorsum  or  posterior  surface  near  its 
upper  edge.  It  extends  from  the  second  to  the  seventh  rib, 
with  its  posterior  margin  parallel  to  and  about  one  inch 
from  the  dorsal  vertebrae.  The  head,  in  which  is  situated 

Coracoid  process. 


Spine. 


Superior  angle 
Supragpinous  fossa. " 


Acromion. 

~~*  Neck  of  scapula . 

Infraspinous  fossa. 


Axillary  border. 


Inferior  angle. 


FIG.  69.— Left  scapula,  posterior  surface  (after  Toldt). 

the  glenoid  cavity  for  articulation  with  the  humerus 
or  upper  arm  bone,  is  surrounded  by  a  slight  con- 
striction, the  neck.  Above  it  projects  the  coracoid 
process,  so  calledjrom  its  fancied  resemblance  to  a  crow's 
beak.  This  can  usually  be  felt  about  one  inch  from 
the  juncture  of  the  outer  and  middle  thirds  of  the  clav- 
icle and  from  it  arise  the  short  head  of  the  biceps  and 
the  coraco-brachialis  muscle.  The  acromion  process 
at  the  end  of  the  spine  extends  out  beyond  the  glenoid 
cavity  posteriorly  and  affords  attachment  to  the  del- 


174  THE    UPPER    EXTREMITIES. 

toid  and  trapezius  muscles.  It  forms  the  sunlmit  of 
the  shoulder.  Numerous  other  muscles  are  attached 
to  the  surface  of  the  scapula,  the  only  parts 
which  are  truly  subcutaneous  being  the  whole  length 
of  the  spine  and  the  acromion  process,  though  the 
lower  angle  and  the  cqracoid  process  can  generally  be 
felt.  The  muscles  bulge  so  much  that  the  spine  in 
the  living  appears  as  a  slight  depression  extending  back 
almost  to  the  vertebrae.  The  large  number  of  the 
muscles  on  the  shoulder  and  arm  is  due  to  the  great 
flexibility  and  strength  required  for  the  various  uses  to 
which  the  arms  are  put. 

Shoulder  Muscles. — The  most  important  shoulder  mus- 
cle is  the  deltoid,  a  large  triangular  muscle,  which  sur- 
rounds and  protects  the  shoulder-joint  and  gives  the 
shoulder  its  rounded  form.  It  rises  from  the  outer  third 
of  the  clavicle,  from  the  acromion  process,  and  from  the 
whole  length  of  the  spine  of  the  scapula,  and  is  inserted 
by  a  tendon  into  a  rough  prominence  on  the  middle  of  the 
outer  side  of  the  humerus.  It  serves  to  raise  the  arm 
and  to  draw  it  somewhat  forward  or  back,  according  as 
the  anterior  or  posterior  fibers  are  used.  The  pectoralis 
major  rises  from  the  inner  half  of  the  clavicle,  the  front 
of  the  sternum,  and  the  cartilages  of  the  true  ribs  and  its 
fibers  converge  to  form  a  fan-shaped  muscle,  which  is  in- 
serted by  a  flat  tendon  into  the  edge  of  the  bicipital 
groove  on  the  humerus.  It  draws  the  arm  forward  and  in- 
ward and  helps  considerably  in  forced  inspiration.  The 
serratus  magnus  rises  from  the  outer  surface  and  upper 
border  of  the  eight  upper  ribs  and  from  an  aponeuro- 
sis  covering  the  upper  intercostal  spaces,  and  is  inserted 
along  the  whole  length  of  the  posterior  border  of 
the  scapula.  It  carries  the  scapula  forward  and  is  used 
in  pushing. 

The  scapula  is  seldom  broken  because  it  is  quite  mov- 
able and  is  covered  with  large  muscles  and  because 
it  lies  on  the  chest,  which  serves  as  an  elastic  cushion. 
The  acromion  process  is  the  part  most  frequently 


THE    UPPER    EXTREMITIES.  175 

broken  and  occasionally  the  neck  is  fractured.  Tumors 
occur  and  may  necessitate  the  amputation  of  the  whole 
upper  extremity. 

The  Humerus. — The  bone  of  the  upper  arm,  the  hu- 
merus, is  the  largest  bone  in  the  upper  extremity  and 
articulates  with  the  scapula  above  and  with  the  ulna 
and  radius  below.  At  its  upper  end  are  the  head  and 
the  anatomical  neck,  with  the  greater  tuber osity  external 
to  and  the  lesser  tuberosity  in  front  of  them.  The  con- 
striction of  the  surgical  neck  is  below  the  tuberosities, 
and  extending  from  between  them  downward  and  in- 
ward along  the  upper  third  of  the  bone  is  the  bicipital 
groove  for  the  long  head  of  the  biceps.  Though  round 
above,  below  the  shaft  becomes  flattened  from  before 
backward  and  curves  slightly  forward,  terminating  in 
the  internal  and  external  condyles,  from  the  former  of 
which  the  flexors  and  the  round  pronator  arise  and 
from  the  latter  the  extensors  and  supinators.  From 
the  external  condyle  also  there  projects  in  front  the  ra- 
dial head  or  capitellum  for  articulation  with  the  radius. 
Internally  to  the  capitellum  in  front  and  in  a  corre- 
sponding position  on  the  back  of  the  bone  are  the  troch- 
lear  surfaces  for  articulation  with  the  ulna,  there  be- 
ing a  depression  in  front  called  the  coronoid  fossa  for  the 
reception  of  the  coronoid  process  of  the  ulna  in  flexion 
of  the  forearm,  and  another  depression  behind,  the 
olecranon  fossa,  to  receive  the  tip  of  the  olecranon 
process  during  extension.  On  the  lower  half  of  the 
humerus  at  the  back  is  the  spiral  groove  for  the  musculo- 
spiral  nerve  and  the  superior  profunda  artery,  while  the 
ulnar  nerve  runs  in  a  groove  back  of  the  internal  condyle. 

The  humerus  is  almost  completely  covered  with  mus- 
cles, the  only  part  that  is  subcutaneous  being  a  small 
portion  of  the  external  and  internal  condyles.  The 
head  can  be  felt  under  the  muscles  and  the  greater 
tuberosity  forms  the  point  of  the  shoulder.  When  the 
arm  is  at  the  side,  the  biceps  appears  at  the  front  and 
inner  side  and  the  brachialis  anticus  on  either  side  be- 


176 


THE    UPPER    EXTREMITIES. 


low,  while  on  the  back  of  the  arm,  with  its  largest  swell- 
ing above,  is  the  triceps. 

Upper  Arm  Muscles. — The  biceps  is  the  most  important 
arm  muscle.  It  rises  by  a  short  head  from  the  coracoid 
process  of  the  scapula  and  by  a  long  head  from  a  tubercle 


FIG.  71. 

FIG.  70. — Superficial  muscles  of  shoulder  and  arm  (from  before):  1,  Pectoralia 
major;  2,  deltoid;  3,  biceps  brachii;  4,  brachialis  anticus;  5,  triceps;  6,  pronator 
radii  teres;  7,  flexor  carpi  radialis;  8,  palmaris  longus;  9,  flexor  carpi  ulnaris;10, 
supinator  longus;  11,  extensor  ossis  metacarpi  pollicis;  12,  extensor  brevis 
pollicis;  13,  flexor  sublimis  digitorum;  14,  flexor  longus  pollicis;  15,  flexor  pro- 
fundus  digitorum;  16,  palmaris  brevis;  17,  abductor  pollicis.  (Borland's  Dic- 
tionary.) 

FIG.  71. — Superficial  muscles  of  shoulder  and  arm  (from  behind) :  1,  Trapezius; 
2,  deltoid;  3,  rhomboideus  major;  4,  infraspinatus;  5,  teres  minor;  6,  teres  major; 
7,  latissimus  dorsi;  8,  triceps;  9,  anconeus;  10,  brachialis  anticus;  11,  supinator 
longus;  12,  extensor  carpi  radialis  longior;  13,  extensor  carpi  radialis  brevior;  14, 
extensor  communis  digitorum;  15,  extensor  carpi  ulnaris;  16,  flexor  carpi  ulnaris; 
17,  extensor  ossis  metacarpi  pollicis;  18,  extensor  brevis  pollicis;  19,  tendon  of 
extensor  longus  pollicis.  (Borland's  Bictionary.) 

on  the  upper  margin  of  the  glenoicl  cavity,  the  tendon 
arching  over  the  head  of  the  humerus  and  descending 
in  the  bicipital  groove.  It  is  inserted  into  the  back  of 
the  tuberosity  of  the  radius  and  by  a  broad  aponeurosis 
into  the  fascia  of  the  forearm.  It  flexes  and  supinates 
the  forearm  and  renders  the  fascia  tense.  Its  inner 


THE    UPPER    EXTREMITIES.  177 

border  forms  a  guide  in  tying  the  brachial  artery,  as  this 
artery  runs  along  its  inner  side. 

The  brachialis  anticus  rises  from  the  lower  half  of  the 
outer  and  inner  surfaces  of  the  humerus  and  is  inserted 
into  the  coronoid  process  of  the  ulna,  thus  covering  and 
proiecting  the  elbow-joint  anteriorly.  It  is  a  flexor  of 
the  forearm. 

Another  smaller  muscle  on  the  anterior  arm,  which 
also  aids  in  flexion,  is  the  coraco-brachialis ,  which  ex- 
tends from  the  coracoid  process  of  the  scapula  to  the 
middle  of  the  inner  surface  of  the  humerus. 

Extending  the  entire  length  of  the  posterior  surface 
of  the  humerus  is  the  triceps,  similar  to  the  quadriceps 
extensor  in  the  thigh  and  direct  antagonist  to  the  bi- 
ceps and  brachialis  anticus  muscles.  It  rises  by  a  long 
head  from  below  the  glenoid  fossa,  by  the  external  head 
from  the  upper  third  of  the  posterior  surface  of  the 
humerus,  and  by  the  internal  head  from  the  middle 
and  lower  thirds  of  the  posterior  surface.  It  is  inserted 
in  the  olecranon  process  of  the  ulna  and  serves  to  extend 
the  forearm  and  arm. 

The  humerus  is  more  often  fractured  by  muscular 
action  than  any  other  bone.  Usually  the  fracture  oc- 
curs in  the  lower  half  of  the  bone  and  sometimes  the 
musculo-spiral  nerve  is  involved.  There  is  a  great  ten- 
dency to  non-union,  probably  due  to  interposition  of 
soft  parts.  Sometimes  the  break  is  across  and  down 
between  the  condyles,  T-fracture.  Involvement  of  the 
elbow-joint  is  more  serious  than  fracture  of  the  humerus 
alone.  Sarcoma  of  the  humerus  does  occur  and  may 
require  the  removal  of  the  clavicle  and  scapula  as  well 
as  of  the  arm  bone  itself.  In  amputation  of  the  hum- 
erus in  children  a  long  skin  flap  is  left  to  allow  for  growth 
of  the  bone,  as  it  is  liable  to  grow  again. 

The  Ulna.— In  the  forearm  there  are  two  bones,  the  ulna 

and  the  radius,  of  which  the  former  is  the  longer.     The 

ulna  is  on  the  inner  side  of  the  forearm  and  its  upper  end 

forms  the  greater  part  of  the  articulation  with  the  humerus, 

12 


178  THE    UPPER    EXTREMITIES. 

as  most  of  the  articulation  at  the  wrist  is  formed  by  the 
radius  and  the  inter-articular  fibro-cartilage.  The  head 
of  the  ulna  is  at  the  lower  extremity  of  the  bone  and 
articulates  on  the  outer  side  with  the  radius  and  below 
with  the  triangular  fibro-cartilage.  From  its  inner  side 
projects  the  styloid  process.  The  olecranon  process 
forms  the  upper  extremity  and  presents  anteriorly  an 
articular  surface,  the  greater  sigmoid  cavity,  for  articula- 
tion with  the  trochlea  of  the  humerus,  where  it  fits  into 
the  olecranon  fossa  during  extension.  The  same  articu- 
lating surface  also  covers  the  coronoid  process,  a  smaller 
projection  below  and  in  front  of  the  olecranon,  which 
fits  into  the  coronoid  fossa  during  flexion.  Continuous 
with  the  greater  sigmoid  cavity  on  the  outer  side  is  the 
lesser  sigmoid  cavity  for  articulation  with  the  head  of  the 
radius.  Under  the  triceps  tendon,  which  is  inserted  into 
the  olecranon,  is  a  bursa  or  sac  of  synovial  membrane, 
such  as  occurs  in  parts  where  much  force  is  brought  to 
bear. 

The  Radius. — The  radius,  or  spoke  of  the  wheel,  is 
on  the  outer  side  of  the  forearm  and  gets  its  name  from 
the  way  it  turns  upon  the  ulna  in  pronation.  The 
shaft  is  larger  below  than  above  and  is  slightly  curved 
longitudinally  for  greater  strength.  The  upper  extrem- 
ity or  head  is  small  and  has  a  slightly  concave  upper 
surface  for  articulation  with  the  radial  head  of  the  hu- 
merus.  It  articulates  by  its  sides  with  the  lesser  sig- 
moid cavity  and  is  bound  to  the  ulna  by  the  orbicular 
ligament,  which  runs  over  a  smooth  articular  surface. 
Below  the  head  is  the  constriction  of  the  neck  with  the 
tuberosity  for  the  biceps  tendon  to  the  inner  side  below. 
The  lower  extremity  is  large  and  forms  the  chief  part  of 
the  wrist-joint,  articulating  with  the  semilunar  and 
scaphoid  bones  of  the  wrist.  From  the  lower  extremity 
the  strong  conical  styloid  process  projects  externally. 

In  the  living  the  olecranon  process  of  the  ulna  is  always 
felt  at  the  elbow  and  the  posterior  border  of  the  ulna 
forms  the  prominent  ridge  down  the  forearm,  leading 


THE    UPPER    EXTREMITIES. 


179 


to  the  styloid  process.  The  head  of  the  radius  is  felt 
just  below  the  external  condyle  and  often  makes  a  dim- 
ple in  the  muscles  of  the  forearm.  The  rest  of  its 


Tuberosity. 


Arterial  foramina.  -.=:--- - 


Radius. ... 


Interosseous  space.  „ 


.-  .Ulna. 


FIG.  72. — Bones  of  the  right  forearm  in  a  position  of  supination.     (Toldt.) 

upper  half  is  concealed  with  muscles,  but  the  lower  half 
is  easily  felt  as  there  are  only  tendons  over  it.  The 
styloid  process  is  felt  externally.  Normally  that  of  the 
radius  is  a  little  lower  than  that  of  the  ulna,  so  that 


180  THE    UPPER    EXTREMITIES. 

in  cases  of  fracture  their  relative  position  is  of  consid- 
erable importance  as  showing  the  amount  of  deformity. 

The  two  forearm  bones  are  more  frequently  broken 
together  than  separately  and  generally  by  direct  vio- 
lence, the  lower  fragment  being  usually  drawn  up  by 
the  action  of  the  flexor  and  extensor  muscles  and  pro- 
ducing a  swelling  on  the  palmar  surface  of  the  forearm. 
Indirect  violence  usually  causes  fracture  of  the  radius 
only.  In  both  cases,  but  especially  in  fracture  of  both 
bones,  there  is  a  tendency  for  membrane  to  get  between 
the  fragments,  so  the  arm  is  put  up  in  splints  with  the 
hand  midway  between  pronation  and  supination  in 
order  to  separate  the  bones  as  far  as  possible.  Care 
must  be  taken  not  to  have  the  bandage  too  tight  or  gan- 
grene of  the  fingers  may  result.  In  most  fractures  of 
the  arm  it  is  put  up  bent,  but  in  fracture  of  the  olecranon 
it  is  put  up  fully  extended,  as  the  fragment  is  sure 
otherwise  to  be  displaced  by  the  pull  of  the  triceps.  In 
fact,  the  olecranon  is  sometimes  fractured  by  the  mus- 
cular force  of  the  triceps,  though  usually  its  fracture, 
which  is  frequent,  is  due  to  direct  violence.  The  ulna 
is  also  often  fractured  in  the  middle  by  direct  violence 
or  the  styloid  process  may  be  broken.  Fracture  of  the 
neck  or  shaft  of  the  radius  is  very  common,  the  most 
important  arm  fracture  being  that  of  the  lower  end 
of  the  radius  or  Colles'  fracture.  This  and  the  corre- 
sponding fracture  in  the  leg,  Pott's  fracture,  are  two  of 
the  commonest  fractures.  In  dislocation  of  the  wrist 
the  normal  relation  of  the  two  styloid  processes  remains 
unchanged,  but  in  Colles'  fracture  the  lower  fragment 
often  projects  on  the  back  of  the  hand,  making  a  typical 
deformity  called  the  silver  fork  deformity. 

The  bones  of  the  wrist  and  hand  had  best  be  de- 
scribed before  the  forearm  muscles  are  taken  up,  as  the 
muscles  of  the  forearm  are  distributed  largely  to  the 
fingers. 

The  Wrist. — The  wrist  or  carpus  is  made  up  of  eight 
bones  arranged  in  two  rows  of  four  each.  In  the  first 


THE    tJPPER    EXTREMITIES.  181 

row  are  the  scaphoid  and  semilunar  bones,  on  the  outer 
side,  articulating  with  the  radius,  the  cuneiform  artic- 
ulating with  the  fibro-cartilage  of  the  wrist-joint,  and 
the  pisiform.  In  the  second  row,  in  corresponding  posi- 
tions, are  the  trapezium,  trapezoid,  os  magnum,  and 
unciform.  The  eminence  felt  on  the  radial  side  of  the 
wrist  is  the  protuberance  of  the  scaphoid,  while  the 
pisiform  is  generally  felt  on  the  ulnar  side. 


FIG.   73.— Right  carpal  bones,  dorsal  surface.     T,  trapezium;  T',  trapezoid; 
7,  os  magnum;  U,  unciform;  S,  scaphoid;  L,  semilunar;  C,  cuneiform,  P,  pisiform. 

The  Hand. — The  hand  contains  nineteen  bones,  five 
metacarpal  bones,  one  for  each  finger  and  the  thumb, 
whose  bases  articulate  with  the  lower  row  of  wrist  bones, 
and  fourteen  phalanges,  three  for  each  finger  and  two 
for  the  thumb,  of  which  the  first  row  articulate  with  the 
metacarpal  bones.  They  are  all  long  bones  and  are 
slightly  concave  anteriorly.  When  the  hand  is  flexed  it 
is  the  heads  of  the  metacarpal  bones,  not  the  bases  of 
the  phalanges,  that  are  so  prominent,  the  head  of  the 
third  metacarpal  being  most  prominent. 

The  metacarpals  are  seldom  fractured,  though  bad 
fractures  occasionally  occur.  In  comminuted  fracture 
nothing  can  be  done  but  remove  the  bone.  If  the  peri- 
osteum is  left  the  bone  will  grow  again.  Two  diseases 


182  THE   UPPEK   EXTREMITIES. 

sometimes  affect  the  metacarpals  and  the  phalanges, 
tuberculosis  and  syphilis.  Both  cause  swelling  of  the 
bones. 

Muscles  of  the  Forearm. — The  chief  groups  of  muscles 
on  the  forearm  are  the  flexors  and  pronators  on  the  an- 
terior surface  and  the  extensors  and  supinators  on  the 
posterior  surface.  In  general  the  flexors  and  pronators 
take  their  origin  from  on  or  around  the  internal  con- 
dyle,  while  the  extensors  and  supinators  arise  on  or 
around  the  external  condyle.  Where  not  otherwise 
stated  it  will  be  understood  that  such  is  their  origin. 
In  a  general  way  they  may  by  grouped  as  follows: 

ANTERIOR  SURFACE. 

[  flexor  carpi  radialis 

Flexors  of  wrist  j  flexor  carpi  ulnaris 

(  palmaris  longus 

f  flexor  sublimis  digitorum 
Flexors  of  fingers  .      , 

[  flexor  profimdus  digitorum 

Flexor  of  thumb  flexor  longus  pollicis 

f  pronator  radii  teres 
Pronators  of  hand 

[  pronator  quadratus 

POSTERIOR  SURFACE. 
Extensor  of  forearm          anconeus 

{extensor  carpi  radialis  longior 
extensor  carpi  radialis  brevior 
extensor  carpi  ulnaris 
extensor  ossis  metacarpi  pollicis 


Extensors  of  thumb 


extensor  primi  internodii  pollicis 


extensor  secundi  internodii  pollicis 
Extensor  of  fingers  extensor  communis  digitorum 

Extensor  of  index  finger   extensor  indicis 
Extensor  of  little  finger    extensor  minimi  digiti 

f  supinator  longus 

Supinators  of  hand  . 

[  supmator  brevis 


THE    UPPER    EXTREMITIES.  183 

Of  the  flexors  of  the  wrist  the  flexor  carpi  radialis  is 
inserted  into  the  base  of  the  index  and  usually  of  the 
third  metacarpal  bone,  the  flexor  carpi  ulnaris  into  the 
fifth  metacarpal,  the  pisiform  and  the  unciform  bones, 
while  the  palmaris  longus  goes  to  the  anterior  annular 
ligament  of  the  wrist  and  the  palmar  fascia  of  the  hand. 
The  flexor  sublimis  digitorum  is  inserted  by  four  tendons 
into  the  second  phalanges  of  the  fingers,  while  the  flexor 
profundus  digitorum  arises  from  the  upper  part  of  the 
ulna  and  is  inserted  into  the  last  phalanges  of  the  fingers. 
The  flexor  of  the  thumb  arises  from  the  middle  of  the 
radius  and  is  inserted  into  the  last  phalanx  of  the  thumb. 
Which  joint  is  flexed  by  a  muscle  depends  upon  the 
origin  and  insertion  of  the  muscle,  all  those  included  be- 
tween being  affected.  Thus,  the  flexor  sublimis  digi- 
torum, which  has  its  origin  in  part  at  least  from  the 
condyle  and  is  inserted  in  the  second  phalanges  of  the 
fingers,  flexes  the  forearm,  wrist,  and  all  the  finger-joints 
but  the  last,  while  the  flexor  profundus  digitorum,  arising 
from  the  ulna,  though  it  flexes  the  wrist  and  fingers,  has 
no  power  of  flexing  the  forearm. 

The  pronator  radii  teres,  besides  arising  from  the  supra- 
condylar  ridge,  rises  from  the  coronoid  process  of  the 
ulna.  It  is  inserted  into  the  middle  of  the  outer  sur- 
face of  the  radius  and  serves  to  pronate  the  forearm. 
The  other  pronator,  the  pronator  quadratus,  is  a  small 
quadrilateral  muscle  extending  transversely  across 
the  radius  and  ulna  just  above  their  carpal  extremities. 
It  rises  from  the  anterior  surface  of  the  ulna  and  is 
inserted  into  the  anterior  external  border  of  the  radius. 

On  the  back  of  the  forearm  the  anconeus  serves  to 
extend  the  forearm  only,  being  inserted  into  the  upper 
part  of  the  posterior  surface  of  the  ulna.  The  exten- 
sors of  the  wrist  are  inserted  into  the  bases  of  the  various 
metacarpal  bones  and  have  some  power  to  extend  the 
forearm  as  well  as  the  wrist.  The  extensors  of  the  thumb, 
as  their  names  imply,  go  one  to  the  metacarpal  bone 
and  one  to  each  of  the  phalanges,  the  longest  one  ex- 


184  THE    UPPER    EXTREMITIES. 

tending  the  whole  thumb,  the  others  only  a  part.  They 
rise  from  the  ulna  and  radius,  not  the  condyle.  The 
extensor  communis  digitorum  goes  to  all  the  phalanges 
of  all  the  fingers,  the  extensor  minimi  digiti  to  those  of 
the  little  finger  only,  and  the  extensor  indicis  to  those 
of  the  index  finger,  the  last  two  arising  short  of  the 
condyle. 

Of  the  supinators  the  longer  one  is  inserted  into  the 
styloid  process  of  the  radius,  while  the  shorter  one,  the 
supinator  brevis,  is  inserted  into  the  upper  part  of  the 
same  bone,  both  thus  serving  to  turn  the  radius  on  the 
ulna. 

Where  the  tendons  of  the  various  muscles  pass  over 
the  wrist,  both  front  and  back,  they  are  covered  with  a 
synovial  sheath  and  are  held  down  by  a  broad  ligament, 
which  some  of  them  perforate,  the  annular  ligament. 
The  strong  fibrous  band  of  the  anterior  annular  ligament 
arches  over  the  carpal  bones  in  front.  Beneath  it  pass 
the  median  nerve  and  the  tendons  of  the  flexors  of  the 
fingers  and  thumb.  The  posterior  annular  ligament  is  of 
less  importance. 

The  deep  palmar  fascia  forms  a  sheath  for  the  muscles 
of  the  hand.  In  carpenters  there  sometimes  occurs 
Dupuytren's  contraction  of  the  palmar  fascia,  which 
draws  the  fingers  up.  As  operation  is  not  always  suc- 
cessful, it  is  quite  a  serious  matter. 

The  muscles  of  the  hand  itself  include  various  abduc- 
tor, adductor,  and  short  flexor  muscles  of  the  thumb 
and  little  finger.  There  also  extend  between  the  meta- 
carpal  bones  the  lumbricales,  four  small  muscles  that 
aid  the  deep  flexor  muscles;  likewise  seven  interossei, 
of  which  four  are  dorsal  and  three  palmar.  The  dorsal 
interossei  arise  by  two  heads  from  the  adjacent  sides 
of  the  metacarpal  bones  and  are  inserted  into  the  bases 
of  the  first  phalanges,  thus  abducting  the  fingers;  while 
the  palmar  interossei,  arising  from  the  palmar  surface 
of  the  second,  fourth,  and  fifth  metacarpals,  are  inserted 
into  the  three  corresponding  first  phalanges  and  adduct 


THE    UPPER    EXTREMITIES.  185 

the  fingers  toward  an  imaginary  line  drawn  through 
the  middle  finger. 

Joints  of  the  Upper  Extremity. — The  joints  of  the  upper 
extremity,  with  the  exception  of  the  wrist-joint,  are  the 
most  freely  movable  of  any  in  the  body,  probably  be- 
cause the  hand  has  the  finest  work  to  do  and  a  greater 
number  of  motions  are  required.  Even  the  wrist  has 
much  greater  freedom  of  motion  than  the  corresponding 
joint  in  the  lower  extremity. 

The  shoulder- joint  is  rather  a  deep  joint,  to  allow  of 
the  varied  motion  required,  and  has  a  capsular  ligament 
from  the  margin  of  the  glenoid  fossa  above  to  the  neck 
of  the  humerus  below.  The  elbow,  which  is  a  hinge 
joint,  has  an  anterior  and  a  posterior  ligament  and 
two  lateral  ligaments,  as  is  practically  the  case  in  all  such 
joints.  The  wrist  has  several  ligaments  which,  taken 
together,  are  capsular  in  nature. 

Blood  Supply  of  the  Upper  Extremity.— The  blood 
supply  of  the  upper  extremity  comes  through  the  sub- 
clavian  artery,  which,  on  the  right,  springs  from  the 
innominate  artery  and  on  the  left  from  the  aortic  arch.  It 
remains  one  trunk  as  far  as  the  elbow,  though  different 
names  have  been  given  to  different  parts.  Thus,  as 
it  passes  over  the  lower  border  of  the  first  rib,  it  becomes 
the  axillary,  and  at  the  lower  border  of  the  axilla, 
where  it  starts  down  the  arm,  the  brachial.  At  the  el- 
bow it  divides  into  the  ulnar  and  radial  arteries. 

In  its  upper  part  the  brachial  artery  lies  internal  to 
the  humerus  but  below  it  is  in  front  of  the  bone.  The 
radial  runs  in  a  line  from  the  middle  of  the  elbow  an- 
teriorly to  the  inner  side  of  the  styloid  process  of  the 
radius  and  is  much  exposed  to  injury  in  the  lower  third 
of  its  course,  as  when  the  hand  is  thrust  through  glass. 
On  it  at  the  wrist  the  pulse  is  counted.  It  is  much 
smaller  than  the  ulnar  and  winds  around  the  outer  side 
of  the  thumb  to  the  palm,  where,  with  the  deep  branch 
from  the  ulnar,  it  forms  the  deep  palmar  arch.  The 
ulnar  artery  passes  obliquely  inward  to  the  middle  of  the 


186  THE    UPPER    EXTREMITIES. 

forearm  and  thence  aiong  its  ulnar  border  to  the  palm 
of  the  hand,  where  it  divides  into  the  deep  branch  and 
the  superficial  palmar  arch  which  supplies  the  four 
digital  arteries. 

From  the  axillary  artery  branches  go  to  the  chest 
wall  and  shoulder,  the  most  important  being  the  two 
circumflex  arteries  to  the  deltoid.  The  brachial  has  only 
two  branches  of  any  importance,  the  superior  and  in- 
ferior profunda,  both  on  the  upper  arm,  of  course. 

In  case  of  hemorrhage  compression  can  frequently 
be  applied  with  the  fingers  where  the  subclavian  crosses 
the  rib  or  in  the  axilla,  where  the  artery  can  be  pressed 
up  against  the  humerus. 

Nerves. — The  nerve  supply  of  the  shoulder  comes 
chiefly  from  the  anterior  and  posterior  thoracic,  the 
suprascapular ,  and  the  circumflex,  these  last  going  to 
the  deltoid.  The  biceps  is  supplied  by  the  musculo- 
cutaneous,  the  triceps  by  the  musculo-spiral ,  and  the 
brachialis  anticus  by  both.  Most  of  the  flexor  and 
pronator  muscles  are  supplied  by  the  median,  while  the 
posterior  interosseous  and  the  musculo-spiral  nerves  go 
to  the  extensors  and  supinators.  The  ulnar  nerve  sup- 
plies the  hand  largely. 


CHAPTER  XIII. 
THE  LOWER  EXTREMITIES. 

The  lower  extremities  resemble  the  upper  very  closely 
in  the  arrangement  of  the  bones,  muscles,  arteries,  and 
nerves,  though  modifications  occur,  due  to  the  difference 
in  function  of  the  lower  limbs.  There  is  one  long  bone 
in  the  upper  part  or  thigh,  the  femur,  and  two  in  the 
lower  part  or  leg,  the  tibia  and  fibula,  while  over  the 
knee-joint  is  the  patella  or  knee  cap.  The  ankle  has 
seven  bones  and  the  foot  nineteen  like  the  hand. 

The  Femur. — The  femur  is  the  longest  bone  in  the 
body,  being  about  one-fourth  the  height  of  the  person. 
It  inclines  toward  its  fellow  at  the  knee  in  order  to 
bring  the  knee-joints  near  the  center  of  gravity  in  walk- 
ing, the  amount  of  inclination  varying  with  the  width 
of  the  hips  and  the  height  of  the  person.  On  account 
of  the  greater  width  of  hip  the  tendency  to  knock- 
knee  is  greater  in  women  than  in  men. 

The  shaft  of  the  femur  is  enlarged  at  the  extremities 
and  is  slightly  curved  forward,  the  concavity  being 
strengthened  at  the  back  by  a  longitudinal  ridge,  the 
linea  aspera,  along  part  of  which  the  gluteus  maximus 
muscle  is  attached.  The  head,  which  is  covered  with 
cartilage,  except  for  an  oval  depression  for  the  attach- 
ment of  the  ligamentum  teres,  one  of  the  ligaments  of 
the  hip  joint,  and  which  articulates  with  the  hollow  of 
the  acetabulum  in  the  os  innominatum,  projects  consid- 
erably upward,  inward,  and  forward  from  the  shaft, 
the  neck  varying  much  in  length  and  angle.  It  is  gen- 
erally more  horizontal  in  women  than  in  men  and  in 
rickets  the  great  weight  on  the  softened  bone  tends  to 
press  the  head  down,  causing  the  deformity  known  as 

187 


188 


THE    LOWER    EXTREMITIES. 


Innominnte  bone. — 


Femur. 


Tibia. 

Fibula.  

Interosseous  space  — 


Patella. 


Metatarsus. 


Tarsus. 


M  fin  tarsus. 


-T.""»  Phalanges. 
Fro.  74.— Bones  of  the  lower  extremity.     (Toldt.; 


THE    LOWER    EXTREMITIES.  189 

"  coxa  vera" ,  in  which  the  neck  is  almost  horizontal. 
Extending  upward,  outward,  and  backward  from  the 
shaft  at  the  base  of  the  neck,  about  three  quarters  of  an 
inch  lower  than  the  head  and  about  on  a  level  with 
the  acetabulum  and  the  spine  of  the  os  pubis,  is  the 
greater  trochanter.  This  large;,  irregular  prominence  and 
the  smaller  one  of  the  lesser  trochanter,  which  is  at  the 
lower  part  of  the  base  of  the  neck  posteriorly,  are  for 
the  attachment  of  muscles  and  to  assist  in  rotating  the 
bone.  The  lower  extremity  of  the  femur  is  larger  than 
the  upper  and  is  flat  from  before  backward.  Between 
its  two  large  eminences,  the  external  and  internal  con- 
dyles,  is  a  smooth  depression  in  front,  the  trochlear 
surface,  for  articulation  with  the  patella.  The  external 
condyle  is  more  prominent  in  front,  the  internal  infe- 
riorly,  the  latter  being  the  longer  of  the  two  by  about  half 
an  inch.  The  epiphysis  at  the  lower  end  of  the  femur 
is  the  only  one  in  which  ossification  has  begun  at  birth. 
Therefore,  if  ossification  is  found  there,  the  child  is  known 
to  have  arrived  at  full  term. 

So  many  large  muscles  are  attached  to  the  femur 
that  the  shaft  cannot  be  detected  in  the  living  unless 
the  person  is  very  thin  and  poorly  developed.  The 
outer  surface  of  the  greater  trochanter,  however,  and 
the  condyles  can  be  felt. 

A  string  stretched  from  the  anterior  superior  spine 
of  the  ilium  to  the  tuberosity  of  the  ischium  passes  in 
the  middle  just  over  the  upper  edge  of  the  greater  tro- 
chanter. The  line  thus  drawn  is  known  as  Ntlaton's 
line  and  is  of  considerable  importance  in  many  condi- 
tions of  the  hip.  Thus,  if  the  hip  is  dislocated,  the  tro- 
chanter will  be  thrown  above  Nelaton's  line,  and  in  os- 
tcomalacia  the  pelvis  sinks  and  the  trochanter  is  again 
a  hove  the  line. 

Thigh  Muscles. — Of  the  thigh  muscles  only  a  few  need 
be  mentioned.  One  large  muscle  is  the  psoas  magnus, 
which  has  its  origin  on  the  front  of  the  last  dorsal  and 
all  the  lumbar  vertebrae,  passes  down  across  the  brim  of 


190  THE    LOWER    EXTREMITIES. 

the  pelvis  and  under  Poupart's  ligament,  gradually  di- 
minishing in  size,  and  terminates  in  a  tendon  that  is 
inserted  into  the  lesser  trochanter.  It  serves  to  flex  the 
thigh  on  the  pelvis  and  to  rotate  it  outward.  The 
psoas  parvus  rises  from  the  last  dorsal  and  the  first 
lumbar  vertebrae  and  does  not  go  out  of  the  pelvis. 

The  sartorius  or  tailor  muscle  is  flat  and  ribbon-like 
and  is  the  longest  muscle  in  the  body.  It  rises  from 
the  anterior  superior  spine  of  the  ilium  and  is  inserted 
into  the  upper  inner  surface  of  the  shaft  of  the  tibia. 
B}'  it  the  legs  are  crossed.  It  also  forms  the  outer 
side  of  an  important  landmark,  Scarpa's  triangle,  whose 
base  is  formed  by  Poupart's  ligament  and  the  inner  side 
by  the  adductor  magnus  muscle,  which  passes  from  the 
ramus  of  the  os  pubis  and  the  tuberosity  of  the  ischium 
to  the  linea  aspera.  The  femoral  artery  bisects  the  tri- 
angle and  runs  into  its  apex. 

The  bulk  of  the  anterior  portion  of  the  thigh  is  formed 
by  the  quadriceps  extensor,  which  is  really  made  up 
of  four  muscles,  the  rectus  femoris,  whose  origin  is  on 
the  anterior  inferior  iliac  spine  and  above  the  acetab- 
ulum;  the  vastus  externus,  which  comes  from  the  greater 
trochanter  and  the  upper  linea  aspera;  and  the  vastus 
internus  and  crureus,  which  rise  from  the  neck  of  the 
femur  and  the  linea  aspera.  It  is  inserted  into  the  tu- 
bercle of  the  tibia  by  the  ligamentum  patella,  in  which 
the  patella  lies.  Its  action  is  to  extend  the  leg. 

At  the  back  and  forming  the  buttocks  are  the  three 
glutei  muscles,  the  glutens  maximus,  medius,  and  mini- 
mus. All  these  rise  from  the  outer  side  of  the  ilium 
and  have  their  insertion  on  or  about  the  great  troc- 
hanter. They  serve  to  hold  the  trunk  erect  and  to 
extend,  abduct,  and  rotate  the  thigh. 

Lower  down  and  forming  the  back  of  the  thigh  are 
the  biceps  and  the  semitendinosus  and  semimembrano- 
sus  muscles.  The  biceps  rises  by  two  heads  from  the 
tuberosity  of  the  ischium  and  the  linea  aspera  and  is 
inserted  into  the  head  of  the  fibula.  It  is  on  the  outer 


THE    LOWER    EXTREMITIES. 


191 


side  of  the  thigh  and  its  tendon,  which  embraces  the 
external  lateral  ligament  of  the  knee-joint,  forms  the 
outer  hamstring.  On  the  inner  side  are  the  semitendi- 
nosus  and  the  semim.embranosus  muscles.  These  rise 


FIG.  75. 


FIG.  76. 


FIG.  77. 


FIG.  75. — Superficial  muscles  of  hip  and  thigh  (from  behind):  1,  Gluteus  me- 
dius;  2,  gluteus  maximus;  3,  vastus  externus;  4,  biceps  flexor  cruris;  5,  semiten- 
dinosus;  6,  semimembranpsus  ;7,  gracilis;  8,  sartorius;  9,  adductor  magnus;  10, 
11,  gastrocnemius;  12,  origin  of  plantaris.  (Borland's  Dictionary.) 

FIG.  76. — Muscles  of  the  inner  side  of  thigh  and  interior  of  pelvis:  1, 
Iliacus;  2,  psoas  magnus;  3,  obturator  internus;  4,  pyriformis1;  5,  erector  spinse; 
6,  gluteus  maximus;  7,  sartorius;  8,  adductor  longus;  9,  gracilis;  10,  adductor 
magnus;  11,  semimembranosus;  12,  semitendinosus;  13,  rectus  femoris;  14,  vas- 
tus internus.  (Borland's  Dictionary.) 

FIG.  77. — Superficial  muscles  of  front  of  thigh:  1,  Insertion  of  external  oblique 
into  iliac  crest:  2,  aponeurosis  of  external  oblique;  3,  external  abdominal  ring; 
4,  gluteus  medius;  5,  tensor  vaginae  formoris;  6,  sartorius;  7,  iliopsoas;  8,  pecti- 
neus;  9,  adductor  longus;  10,  gracilis;  11,  adductor  magnus;  12,  vastus  exter- 
mus;  13,  rectus  femoris;  14,  vastus  internus;  15,  biceps  flexor  cruris.  (Dorland'a 
Dictionary.) 

from  the  tuberosity  of  the  ischium  and  are  inserted, 
the  one  into  the  upper  inner  surface  of  the  shaft  of  the 
tibia  and  the  other  into  the  internal  tuberosity  of  the 
tibia.  Their  tendons  form  the  inner  hamstring.  Like 
the  biceps  they  serve  to  extend  the  thigh  and  flex  the 


192  THE    LOWER    EXTREMITIES. 

leg  on  the  thigh,  but  where  the  biceps  rotates  the  leg 
out  they,  being  attached  to  the  inner  side  of  the  leg 
bones,  rotate  it  in. 

The  patella,  or  small  pan,  is  a  flat,  somewhat  triangular 
bone  developed  in  the  quadriceps  extensor  tendon.  Four 
muscles  are  attached  to  it  as  well  as  the  ligamentum 
patellae,  which  holds  it  to  the  tibia  and  gives  increased 
leverage  by  making  the  quadriceps  extensor  work  at  a 
greater  angle.  It  articulates  with  the  condyles  and 
serves  to  protect  the  joint.  One  bursa,  the  prepatella 
bursa,  separates  it  from  the  skin  and  another,  surrounded 
by  adipose  tissue,  from  the  head  of  the  tibia.  The  ex- 
ternal surface  can  be  seen  and  felt  on  the  front  of  the 
knee  and  the  bone  can  be  moved  from  side  to  side  when 
the  leg  is  straight. 

Joints  of  the  Lower  Extremity. — The  hip-joint  is  a 
ball-and-socket  joint  but  is  not  so  freely  movable  as 
the  shoulder-joint,  the  head  of  the  femur  being  held  in 
the  acetabulum  by  many  strong  ligaments,  of  which  the 
most  important  is  the  capsular  ligament. 

The  knee-joint  is  largely  a  hinge-joint,  but  in  some 
positions  it  has  some  rotation.  It  is  formed  by  the  con- 
dyles of  the  femur,  the  head  of  the  tibia,  and  the  patella, 
and  has  fourteen  ligaments,  including  the  ligamentum 
patella?  and  the  crucial  ligaments.  Its  synovial  sac 
is  the  largest  found  in  any  joint.  Two  semilunar 
cartilages,  placed  on  the  head  of  the  tibia,  serve  to  deepen 
the  socket  for  the  condyles,  changing  somewhat  in  shape 
and  thickness  as  the  joint  moves.  The  interval  between 
the  thigh  and  the  leg  bones  can  be  felt  at  the  knee. 
When  the  leg  is  extended  the  juncture  of  the  bones  is 
slightly  above  the  patella,  while  in  flexion  a  knife  passed 
below  the  apex  of  the  patella  will  pass  into  the  joint. 

Congenital  dislocation  of  the  hip  occurs.  Separation  of 
the  epiphysis  of  the  femur  may  occur  and  sometimes  the 
neck,  rarely  the  lower  part  of  the  shaft,  is  fractured. 
Either  condyle  may  be  fractured  off  or  there  may  be  a 
T-fracture,  in  which  case  the  popliteal  artery  may  be 


THE    LOWER   EXTREMITIES. 


193 


injured.  In  dislocation  the  head  may  be  behind  or  in 
front  of  the  acetabulum.  Impacted  hip,  where  the  neck 
of  the  femur  has,  in  a  fall,  been  driven  into  the  head,  is 
common  in  old  people.  Sometimes,  especially  in  young 
children,  the  bone  is  infected,  osteomyelitis.  Sarcoma 
occurs.  Most  tubercular  disease  of  the  hip  originates  at 
the  upper  extremity  of  the  femur,  tuberculosis  generally 


FIG.  78. 


FIG.  79. 


Fro.  78. — Right  knee-joint,  posterior  view.     (Leidy.) 

FIG.  79.— Right  knee-joint,  showing  internal  ligaments:  2,  anterior  crucial 
ligament;  3,  posterior  crucial  ligament;  4,  transverse  ligament;  6,  7,  semilunar 
fibroeartilages.  (Leidy.) 

starting  in  the  head  and  then  attacking  trie  capsule  and 
the  soft  parts  of  the  joint.  If  neglected,  shortening  of 
the  leg  may  result,  in  which  case  the  bone  has  to  be 
broken  and  set  at  an  angle  in  order  to  enable  the  child  to 
walk. 

Occasionally  a  bit  of  cartilage  gets  broken  off  in  the 
knee-joint  and  wedged  between  the  bones,  so  that  the 
joint  cannot  be  straightened.  This  is  dislocation  of  the 
semilunar  cartilage  and  necessitates  an  operation  for 
removal  of  the  piece.  The  cartilage  will  eventually  be 
replaced  by  fibrous  tissue  and  in  a  few  months  the  leg 

13 


194  THE   LOWER    EXTREMITIES. 

will  be  all  right.  Dislocation  of  the  knee  is  rare,  though 
it  may  occur  in  any  direction.  Often  the  bursae  of  the 
joint  are  irritated,  as  by  kneeling  to  scrub  floors,  and 
bursitis  or  housemaid's  knee  results.  Fracture  of  the 
patella  may  be  caused  by  muscular  traction  or  by  direct 
violence,  and  is  generally  repaired  by  making  an  incision 
and  sewing  the  parts  of  the  bone  together.  Tumor  albus 
or  white  swelling  is  tuberculosis  of  the  knee  and  is  fairly 
common  in  children.  Specific  knee  means  syphilis  of  the 
knee  and  generally  occurs  in  both  knees. 

The  Tibia. — The  tibia  or  shin  bone  is  next  longest 
to  the  femur  and  is  on  the  inner  side  of  the  leg,  corre- 
sponding to  the  ulna  in  the  arm.  The  shaft  is  prismoid 
and  is  more  slender  for  the  lower  quarter,  where  fracture 
is  consequently  most  frequent.  The  anterior  border 
forms  the  crest  or  shin  and  can  be  felt  for  its  upper  two- 
thirds.  The  lower  extremity,  which  is  smaller  than 
the  upper,  articulates  with  the  astragalus  bone  of  the 
ankle  and  with  the  fibula.  Its  head  or  upper  extremity 
is  expanded  into  two  lateral  tuberositis  for  articulation 
with  the  femur  and  for  muscular  attachment,  both  of 
which  can  easily  be  felt  just  below  the  bend  of  the  knee. 
Their  upper  surfaces  are  smooth  and  concave,  with  a 
vertical  bifid  spine  in  the  middle  and  a  prominent 
tubercle  for  the  attachment  of  the  scmilunar  cartilages 
on  either  side.  On  the  anterior  surface  of  the  head, 
below,  is  a  rough  eminence  or  tubercle,  which  also  can  be 
felt.  The  lower  part  of  this  is  for  the  attachment  of  the 
ligamentum  patellae,  while  the  upper  part,  which  is 
smoother,  is  for  the  bursa  that  is  placed  under  the  tendon 
to  prevent  friction.  On  the  back  of  the  outer  tuberosity 
is  a  facet  for  the  head  of  the  fibula.  At  the  lower  end 
there  projects  downward  on  the  inner  side,  overhanging 
the  arch  of  the  foot,  the  internal  malleolus,  the  prominent 
part  of  the  ankle.  It  is  on  a  higher  level  and  somewhat 
farther  forward  than  the  external  malleolus. 

The  Fibula. — The  fibula  is  the  most  slender  of  all  the 
bones  in  proportion  to  its  length  and  is  on  the  outer  side 


THE    LOWER    EXTREMITIES.  195 

of  the  leg.  Its  head  is  small  and  placed  toward  the 
back  of  the  tibia  below  the  knee-joint,  from  which  it  is 
excluded.  The  head  articulates  with  the  external 
tuberosity  and  has  extending  upward  from  it  the  styloid 
process.  To  it  is  attached  the  biceps  tendon  or  outer 
hamstring.  At  the  lower  extremity  of  the  shaft  is  the 
external  malleolus,  which  articulates  with  the  astragalus 
and  forms  the  outer  ankle.  The  only  parts  of  the  fibula 
that  can  be  felt,  besides  the  malleolus,  which  is  very 
prominent,  are  the  head  and  the  lower  external  surface 
of  the  shaft. 

In  fracture  of  the  leg  both  bones  are  usually  broken, 
though  either  may  be  broken  separately.  Pott's  fracture 
is  fracture  of  the  lower  fibula,  and  may  be  caused  by 
stamping  hard  when  stepping  on  to  the  sidewalk.  In 
rickets  the  tibia  becomes  bowed  outward  and  forward, 
causing  bow  leg,  a  condition  which  in  very  young  children 
may  be  rectified  by  manipulation.  Later  on  braces  are 
needed  and  after  five  years  the  bones  have  to  be  broken 
and  set  straight. 

The  Ankle. — The  ankle  or  tarsus  has  but  seven  bones 
where  the  wrist  has  eight.  They  are  the  os  calcis  or 
heel  bone,  which  is  the  largest  and  strongest  and  forms 
the  tuberosity  of  the  heel;  the  astragalus,  which  is  next 
largest  and  helps  to  form  the  ankle-joint;  the  cuboid;  the 
navicular  (boat-like)  or  scaphoid;  and  the  internal,  mid- 
dle, and  external  cuneiform  bones.  The  astragalus  is 
above  and  partially  in  front  of  the  os  calcis,  to  which  is 
attached  the  tendo  Achillis.  The  cuboid  is  on  the  outer 
side  of  the  foot,  in  front  of  the  os  calcis  and  behind  the 
metatarsals.  It  is  noticeable  in  congenital  club-foot,  in 
which  condition  the  tarsal  bones  may  be  distorted  in 
shape  and  misplaced.  The  navicular  or  scaphoid  is  on 
the  inner  side  of  the  foot,  between  the  astragalus  and 
the  three  cuneiform  bones. 

The  Foot. — There  are  five  metatarsal  bones  in  the  foot, 
corresponding  to  the  five  metacarpals  in  the  hand,  and 
the  toes  have  the  same  number  of  phalanges  as  the 


196  THE    LOWER    EXTREMITIES. 

fingers,  though  they  are  shorter  and  stronger.     The  big 
toe  corresponds  to  the  thumb. 

Fracture  of  the  os  calcis  and  the  astragalus  are  most 
commonly  caused  by  a  fall  from  a  height,  while  the 
metatarsals  and  phalanges  are  generally  broken  by  some- 
thing heavy  falling  upon  them.  Because  of  their  delicate 
structure,  their  distance  from  the  heart,  and  the  differ- 


FIG.  80. — Bones  of  the  right  foot,  dorsal  surface:  1,  Astragalus;  3,  os  calcis, 
4,  navicular;  5,  internal  cuneiform;  6,  middle  cuneiform;  7,  external  cuneiform; 
8,  cuboid;  9,  metatarsus;  10-14,  phalanges.  (Leidy.) 

ences  of  temperature  to  which  they  are  subjected,  the 
tarsal  bones  are  especially  liable  to  become  tubercular, 
amputation  of  the  feet  even  becoming  necessary  at  times. 
In  diabetes  there  may  be  a  perforating  ulcer  on  the  sole 
of  the  foot  and  the  bone  may  become  diseased. 

Muscles  of  the  Leg. — The  greater  part  of  the  calf  of  the 
leg  is  formed  by  the  gastrocnemius ,  a  large  bulging  mus- 
cle, which  rises  from  the  condyles  of  the  femur  and  is 
inserted  along  with  the  soleus,  whose  origin  is  on  the 


THE    LOWER    EXTREMITIES. 


197 


back  of  the  upper  fibula,  and  the  plantaris,  which  comes 
from  the  linea  aspera,  into  the  os  calcis  by  a  common  ten- 
don, the  tendo  Achillis,  the  largest  and  strongest  tendon 
in  the  body.  Its  action  is  to  extend  the  foot  and  to 


FIG.  81. 


FIG.  82. 


FIG.  83 . 


FIG.  81. — Superficial  muscles  of  the  leg  from  inner  side:  1,  Vastus  internus;  2, 
sartorius;  3,  gracilis;  4,  semitendinosus ;  5,  semimembranosus;  6,  inner  head  of 
gastrocnemius;  7,  soleus;  8,  tendon  of  plantaris;  9,  tendon  of  tibialis  posticus;  10, 
flexor  longus  digitorum;  11,  flexor  longus  hallucis;  12,  tibialis  anticus;  13,  ab- 
ductor hallucis.  (Borland's  Dictionary.) 

FIG.  82. — Muscles  of  leg  and  foot  (from  before):  1,  Tendon  of  rectus  femoris; 
2,  vastus  internus;  3,  vastus  externus;  4,  sartorius;  5,  iliotibial  band;  6,  inner 
head  of  gastrocnemius;  7,  inner  part  of  soleus;  8,  tibailis  anticus;  9,  extensor 
proprius  hallucis;  10,  extensor  longus  digitorum;  11,  peroneus  longus;  12,  pero- 
neus  brevis;  13,  peroneus  tertius;  14,  origin  of  extensor  brevis  digitorum. 
(Borland's  Dictionary.) 

FIG.  83. — Superficial  muscles  of  leg  (from  behind) :  1,  Vastus  externus;  2,  biceps 
flexor  cruris;  3,  semiteTidinosus;  4,  semimembranosus;  5,  gracilis;  6,  sartorius;  7, 
outer,  and  8,  inner,  head  of  gastrocnemius;  9,  plantaris;  10,  soleus;  11,  peroneus 
longus;  12,  peroneus  brevis;  13,  flexor  longus  digitorum;  14,  tibialis  posticus;  15, 
lower  fibers  of  flexor  longus  hallucis.  (Dorland's  Dictionary.) 

rotate  it  slightly  inward.  Other  extensors  of  the  foot, 
which  also  evert  it,  are  the  peroneus  longus  and  the 
peroneus  brevis  at  the  upper  and  outer  part  of  the  leg,  the 
former  rising  from  the  outer  tuberosity  of  the  tibia  and 


198  THE   LOWER    EXTREMITIES. 

the  upper  fibula  and  being  inserted  into  the  first  metatar- 
sal  and  the  internal  cuneiform,  the  latter  arising  from  the 
lower  fibula  and  being  inserted  into  the  fifth  metatarsal. 
The  foot  is  flexed,  adducted,  and  rotated  inward  by 
means  of  the  tibialis  anticus,  which  rises  from  the  outer 
tuberosity  and  the  upper  two-thirds  of  the  outer  surface 
of  the  tibia  and  is  inserted  into  the  internal  cuneiform 
bone. 

In  the  foot,  and  corresponding  to  the  palmar  fascia  in 
the  hand,  is  the  plantar  fascia,  the  densest  of  all  fibrous 
membranes.  There  are  also  various  annular  ligaments, 
and  the  foot  muscles  are  arranged  similarly  to  those  in  the 
hand. 

The  Blood  Supply  of  the  Lower  Extremity.— The 
blood  supply  of  the  lower  extremity  comes  from  the 
external  iliac  artery ,  a  branch  of  the  common  iliac, 
which  passes  obliquely  downward  and  outward  along 
the  border  of  the  psoas  muscle  to  Poupart's  ligament, 
where  it  enters  the  thigh  and  becomes  the  femoral  artery. 
Its  only  important  branches  are  the  deep  epigastric, 
which  goes  up  along  the  internal  abdominal  ring,  and  the 
deep  circumflex  iliac.  As  the  femoral  artery  it  passes 
down  the  inner  side  of  the  thigh  to  the  internal  condyle 
of  the  femur,  being  very  superficial  at  Scarpa's  triangle, 
where  it  can  be  compressed  with  the  thumb  to  stop 
hemorrhage  below.  If  a  tourniquet  is  applied,  it  should 
be  applied  a  little  lower  down.  The  first  and  most 
important  branch  of  the  femoral  is  the  profunda  femoris. 

About  two-thirds  of  the  way  to  the  knee  the  artery 
takes  the  name  popliteal.  It  lies  superficially  in  the 
popliteal  space  back  of  the  knee,  but  above  and  below  it 
is  covered  with  muscles.  Its  branches  supply  the  knee- 
joint  and  nearby  muscles  and  are  unimportant.  At  the 
lower  border  of  the  popliteus  muscle,  a  small  muscle  at  the 
knee,  it  divides  into  the  anterior  and  posterior  tibial 
arteries.  The  course  of  the  former  of  these  may  be  marked 
by  a  line  from  the  inner  side  of  the  head  of  the  fibula  to 
midway  between  the  malleoli  at  the  front  of  the  ankle, 


THE    LOWER    EXTREMITIES.  199 

where  it  terminates  in  the  dorsalis  pedis  artery  for  the 
back  of  the  foot.  By  this  last  the  pulse  is  sometimes 
taken  and  its  pulsation  is  a  guide  in  determining  how 
high  up  to  amputate  in  gangrene  of  the  foot.  The 
posterior  tibial  extends  obliquely  down  the  back  of  the 
leg  to  the  heel,  where  it  divides  into  the  internal  and 
external  plantar  arteries  which  go  to  the  sole  of  the  foot. 
Its  most  important  branch  is  the  peroneal. 

Besides  the  deep  veins  accompanying  the  arteries 
there  are  the  superficial  veins,  the  internal  or  long  saphen- 
ous  on  the  inner  side  of  the  leg  and  thigh  and  the  external 
or  short  spahenous  on  the  middle  of  the  leg  posteriorly 
and  emptying  into  the  popliteal  vein.  Varicosity  often 
occurs  in  these  veins. 

Nerves. — The  nerves  of  the  muscles  about  the  hip  are 
branches  of  the  lumbar  nerve.  The  anterior  crural  sup- 
plies the  anterior  part  of  the  thigh,  the  gluteal  the 
muscles  of  the  same  name,  and  the  great  sciatic  the  large 
muscles  of  the  back  of  the  thigh.  Below  the  knee  the 
anterior  tibial  goes  to  the  tibialis  anticus  and  the  in- 
ternal popliteal  to  the  muscles  of  the  calf,  while  the 
peroneus  muscles  are  supplied  by  the  musculo-cutaneous. 


NDEX. 


ABDOMEN,  132 

muscles,  132,  et  seq. 

nerves,  134 

regions,  134,  135 

contents,  135,  136 
Abdominal  aorta,  107,  109 
Abducens  nerve,  83 
Abscess,   34,    51,   52,   100,  137, 

152,  159,  168 

Absorbent    vessels    or    lymph- 
atics, 34 

Absorption  of  food,  33 
in  intestines,  144 
in  mouth,  136 
in  stomach,  140 
Accommodation  of  eye,  72 
Acetabulum,  162,  187 
Acromion  process,  173 
Adam's  apple,  121 
Adductor  magnus  muscle,  190 
Adenoids,  62 
Adipose  tissue,  16 
Air,  changes  by  breathing,  129, 
130 

complemental,  129 

residual,  129 

supplemental,  129 

tidal,  129 
Air  cells,  27 
Albumin  in  urine,  158 
Albuminoids,  12 
Alimentary  canal,  136,  et  seq. 
Alveoli  of  lungs,  126 


Amoeba,  12 

Ampulla3  of  mamma  or  breast, 

100 

Amputation,  177 
Amylopsin,  144 
Anabolism,  147 
Anasarca,  152 
Anatomy,  11 

Anconeus  muscle,  182,  183 
Anemia,  120 
Aneurism,  109 
Ankle,  195 

Annular  ligaments,  184,  198 
Ano-spinal  reflex,  146 
Antrum  of  Highmore,  54,  57 
Anus,  141,  146 
Aorta,  99,  107,  109 
Aortic  valve,  104 
Aponeuroses,  23 
Apoplexy,  79,  118 
Appendages  of  the  skin,  40 
Appendix,  vermiform,  145 
Aqueous  humor,  70 
Arachnoid,  76 
Areola,  100 
Areolar  tissue,  15 
Arteries,  27,  28,  29,  107 

nerves,  29 

of  back,  94,  95 

of  brain,  77 

of  breast,  100 

of  chest,  99 

of  heart,  107 


201 


202 


INDEX. 


Arteries  of  intestine,  143,  145 
of  kidney,  156 
of  lower  extremity,  198,  199 
of  organs  of  generation,  168 
of  pancreas,  153 
of  spleen,  153 
of  stomach,  139 
of  upper  extremity,  185,  186 
structure,  27 
Artery,  axillary,   99,    100,    108, 

185 

basilar,  77,  108 
brachial,  108,  177,  185 
carotid,  common,  107,  108 

internal  and  external,  108, 

137 

celiac  axis,  109,  143,  150,  153 
cerebral,  77 
circumflex,  186 
coronary,  107 
communicating,  78 
digital,  186 
dorsalis  pedis,  199 
epigastric,  deep,  198 
facial,  28 
femoral,  190,  198 
gastric,  109 
hepatic,  109,  150 
iliac,  common,  107,  109 

internal  and  external,  95, 
109,  198 

circumflex,  198 
innominate,  107 
intercostal,  95,  97,  100,  108 
lumbar,  95,  109 
mammary,  internal,  99,  100, 

108 

mediastinal,  99 
mesenteric,  109,  143,  145, 153 
ophthalmic,  70 
peroneal,  199 
phrenic,  99,  109 


Artery,     plantar,   internal    and 

external,  199 

popliteal,  198 

profunda,    superior    and    in- 
ferior, 175,  186 
femoris,  198 

pudic,  168 

pulmonary,  106,  110 

radial,  108,  185 

renal,  109 

spermatic  or  ovarian,  109, 168 

splenic,  109,  153 

subclavian,  94,  99,  107,  108 
185 

suprarenal,  109 

suprascapular,  94 

thyroid  axis,  108 

tibial,  198 

transversalis  colli,  94 

ulnar,  108,  185 

umbilical,  107 

uterine,  168 

vertebral,  77 
Arytenoid  cartilages,  122 
Ascending  aorta,  107 

colon,  145 
Ascites,  34,  152 
Asphyxia,  128 
Astigmatism,  73 
Astragalus,  195 
Atlas,  91 
Auditory  meatus,  52 

canal,  external,  63 
internal,  64 

center,  81 

nerve,  64,  65,  84 
Auricles  of  heart,  103 
Axilla,  32 
Axillary  artery,  99,     100,     108, 

185 

Axis,  91 
Axis-cylinder  process,  36,  37 


INDEX. 


203 


BACK,  88,  et  seq. 

muscles,  93,  94 

arteries,  94,  95 

nerves,  95 

Basilar  artery,  77,  108 
Basilic  vein,  109 
Biceps  of  arm,  175,  176 

of  leg,  190,  191 
Bicipital  groove,  175 
Bicuspid  or  mitral  valve,  104 

teeth,  60 
Bile,  36,  143,  150 
Bilirubin,  12,  143,  151 
Biliverdin,  143,  151 
Bladder,  160 
Blind  spot,  70 
Blood,  27,  116,  et  seq. 

amount,  116 

arterial  and  venous,  29 

circulation  of,  29,  105,  et  seq. 

coagulation,  117,  118 

coloring  matter,  119 

composition,  116,  117 

corpuscles,  116,  118,  et  seq. 

fibrin,  117 

functions  of,  116 

plaques,  120 

plasma,  33,  116,  117 

pressure,  114,  115 

serum,  117 

vessels,  27,  et  seq. 
Bone,  17 

astragalus,  195 

atlas,  91 

axis,  91 

canaliculi,  17 

cancellous  or  spongy,  17 

carpal,  180,  181 

chemical  composition,  18 

clavicle,  171 

coccyx,  90,  161 

compact,  17,  18 


Bone,  cuboid,  195 
cuneiform,  181,  195 
endosteum  of,  18 
ethmoid,  48,  53 
femur,  187 
fibula,  194,  195 
formation  of,  18 
frontal,  49 

Haversian  canals  of,  17 
humerus,  175 
hyoid,  60 
ilium,  161,  162 
incus,  63 

innominate,  161,  162 
ischium,  161,  163 
lachrymal,  48,  54 
lacunae  of,  17 
lamellae  of,  17 
malar,  48,  54 
malleus,  63 
marrow  of,  18 
maxillary,  inferior,  48,  55 

superior,  48,  54 
metacarpal,  181 
metatarsal,  195 
nasal,  48,  55 
navicular,  195 
occipital,  48,  50 
os  calcis,  195 
os  innominatum,  161,  162 
os  magnum,  181 
palate,  48,  54 
parietal,  48,  49 
patella,  19  ,  192 
pelvis,  161 
periosteum  of,  18 
phalanges,  of  foot,  195 

of  hand,  181 
pisiform,  181 
pubes,  161,  163 
radius,  178,  179 
ribs,  97,  98 


204 


INDEX. 


Bone,  sacrum,  90,  161 

scaphoid,  181,  195 

scapula,  173 

semilunar,  181 

sphenoid,  48,  52 

stapes,  63 

sternum,  97 

structure  of,  17 

tarsal,  195 

temporal,  48,  51 

tibia,  194 

trapezium,  181 

trapezoid,  181 

turbinated,  53 

inferior,  48,  53,  54 

ulna,  177,  178 

unciform,  181 

vertebrae,  88 

vomer,  48,  55 
Bones,  classification  of,  19 

flat,  20 

function  of,  19,  20 

long,  19 

of  back,  88 

of  chest,  97,  98 

of  cranium,  48,  et  seq. 

of  face,  53,  et  seq. 

of  lower  extremity,  187,  etseq. 

of  upper  extremity,  171,  et  seq. 

pelvic,  161,  et  seq. 

sesamoid,  19 

short,  20 

Wormian,  19,  49 
Bow  leg,  195 
Brachial  artery,  108,  177,  185 

plexus,  84,  85 
Brachialis  anticus,  175,  177 
Brain,  75,  et  seq. 

areas,  81,  82 

arteries,  77 

function,  80,  et  seq. 

parts,  75 


Broad  ligaments  of  uterus,  165, 

166,  168 

Bronchi,  123,  125 
Buffy  coat,  117 
Bursse,  synovial,  20,  178 
Bursitis,  194 
Buttocks,  190 

CANAL,  alimentary,  136,  et  seq. 

auditory,  63,  64 

central,  of  cord,  81 

Haversian,  17 

semicircular,  64,  66 
Canaliculi  of  bone,  17 
Cancellous  tissue  of  bone,  17 
Cancer,   35,    58,   62,    100,  122, 

139,  146,  169 
Canine  teeth,  60 
Canthus  of  eye,  67,  68 
Capillaries,  28,  29 
Capitellum,  175 
Capsular  ligament  of  hip,  193 
Carbohydrates,  12,  26,  147,  148, 

151 
Cardiac  cycle,  104 

muscle,  22,  25 

nerve,  78 

plexus,  87 
Caries,  98 
Carotids,  common,  107,  108 

internal  and  external,   108, 

137 

Carpal  bones,  180,  181 
Carpus  or  wrist,  180,  181 
Cartilage,  16 
Cartilages,  arytenoid,  122 

costal,  98 

cricoid,  121 

thyroid,  121 

triangular,  57 
Casein,  11 
Cauda  equina,  79,  91 


INDEX. 


205 


Cecum,  145 

Celiac  axis,  109,  150,  153 

Cells,  12,  13 

Central  canal  of  cord,  81 

Cephalocele,  53 

Cerebellum,  51,  78 

Cerebral  arteries,  77 

veins,  78 

Cerebro-spinal  fluid,  34,  76,  79 
meningitis,  79 
nervous  system,  75,  et  seq. 
Cerebrum  or  brain  proper,  51, 

75 

Cervical  nerves,  84 
plexus,  84 
vertebrae,  90,  91 
Cervix  of  uterus,  168 
Chemical    composition    of    the 

body,  11 
of  bone,  18 
Chest  or  thorax,  96 
arteries,  99 
bones,  97,  98 
muscles,  98,  99 
nerves,  99 
Cholesterin,  143 
Chorda  tendineae,  104 
Choroid,  68 

Chromatic  aberration,  73 
Chyle,  32,  33,  144 
Chyme,  139,  140 
Cilia,  15,  27 
Ciliary  muscles,  69,  72 

processes,  69,  72 
Circle  of  Willis,  78,  108 
Circulation  of  the  blood,  fetal, 

106,  107 
portal,  109,  110 
pulmonary,  110 
systemic,     105,    106,    107, 

et  seq.,  112,  113 
Circumflex  artery,  186 


Circumflex  nerve,  85,  186 
Circumvallate  papilhe,  61 
Cirrhosis  of  liver,  152 
Clavicle,  171 
Cleft  palate,  55 
Clitoris,  170 

Clotting  of  blood,  23,  117,  118 
of  lymph,  33 
of  muscle,  23  . 
Club-foot,  195 
Coccygeal  nerve,  84 

vertebra,  90 
Coccyx,  90,  161 
Cochlea,  64,  65 
Colics'  fracture,  171,  180 
Color  blindness,  73 

perception,  73 
Coloring  matters,  12 

of  bile,  143,  151 

of  blood,  119 
Colon,  ascending,  145 
descending,  145 
transverse,  145 
Columnar  carnese,  104 
Commissures  of  cord,  80 
Common  bile  duct,  150 
Communicating  arteries,  78 
Compact  tissue  of  bone,  17,  18 
Condyles,  humerus,  175 

femur,  189 
Conjunctiva,  67 
Conjugate  focus,  71 
Convolutions  of  brain;  76 
Connective  tissue,  15,  et  seq. 

areolar,  15 

bony,  17 

cartilaginous,  16 

elastic,  15 

fatty  or  adipose,  16 

fibrous,  15 

Coraco-brachialis,  177 
Coracoid  process  of  scapula,  173 


206 


INDEX. 


Cordiform  tendon,  98 
Cornea,  27,  68,  70 
Cornicula  laryngis,  122 
Coronary  artery,  107 

sinus,  105 

valve,  105 
Coronal  suture,  48 
Coronoid  fossa,  175 

process,  178 
Corpus  luteum,  166 
Corpuscles  of  blood,  116,  118, 
et  seq. 

tactile,  37,  39,  46 
Corti,  organ  of,  65 
Costal  cartilages,  98 
Coughing,  131 
"Coxa  vera,"  189 
Cranial  nerves,  77,  78,  83,  84 
Craniotabes,  53 
Cranium,  bones  of,  48,  et  seq. 
Cribriform   plate   of   ethmoid 

bone,  53 

Cricoid  cartilage,  121 
Crista  galli,  53 
Cross  eye,  72 

Crossed  pyramidal  tract,  82 
Crucial  ligaments,  193 
Crural  nerves,  85,  199 
Crureus,  190 
Crying,  131 
Crypts  of  Lieberkuhn,  143,  144, 

145 

Crystalline  lens,  69,  70 
Cuboid  bone,  195 
Cuneiform  bones,  ankle,  195 

wrist,  181 
cartilages,  122 
Cutaneous  nerves,  46,  85 
Cystic  duct,  143,  152 

DELTOID,  174 
Dendrites,  36 


Derma,  39 
Descending  aorta,  107 

colon,  145 

Diabetes  mellitus,  151,  196 
Diaphragm,  98,  99,  128 
Diaphysis,  18 
Diastole,  104,  106 
Differentiation  of  tissues,  13 
Digestion,  in  mouth,  136 

in  small  intestine,  143,  144 

in  stomach,  139,  140 

of  fats,  144 

of  proteids,  140,  144 

of  starch,  136,  144 
Digital  arteries,  186 
Diphtheria,  35 
Diploe,  20,  48 
Direct  cerebellar  tract,  82 

pyramidal  tract,  80,  82 
Dislocation,  180,  193,  194 
Diuretics,  158 

Dorsal  or  thoracic  nerves,  84, 
85 

vertebra?,  90,  91 
Dorsalis  pedis  artery,  199 
Duct,  common  bile,  150 

cystic,  143,  152 

ejaculatory,  165 

hepatic,  143,  150 

lachrymal,  68 

of  Rivinus,  62 

pancreatic,  153 

right  lymphatic,  31,  32 

Stensen's,  62 

Wharton's,  62 
Ductless  glands,  36 
Ductus  arteriosus,  106,  107 

communis  choledochus  or 

common  bile  duct,  150 
Duodenum,  142 
Dupuytren's  contraction,  184 
Dura  mater,  15,  76,  79 


INDEX. 


207 


EAR,  63,  et  seq. 

external,  63 
function  of,  65 

internal,  64 
function  of,  65 

middle,  63 

function  of,  65 
Edema,  33,  34,  122 
Eighth  nerve,  64,  84 
Ejaculatory  duct,  165 
Elbow,  32 

joint,  185 
Elastic  tissue,  15 
Eleventh  nerve,  84 
Emmetropic  eye,  72 
Emphysema,  97 
Empyema  of  gall-bladder,  152, 
153 

of  lungs,  126 
End  bulbs,  37 
Endocardium,  103 
Endolymph,  64,  65 
Endosteum,  18 
Endothelium,  14,  40 
Ensiform  cartilage,  97 
Epidermis,  27,  39 
Epigastric  artery,  198 
Epigastrium,  135 
Epiglottis,  60,  121,  136 
Epiphysis,  18,  189,  193 
Epithelium,  14,  27 

ciliated,  15,  27 

columnar,  14 

glandular,  14 

pavement,  14 

simple,  14 

stratified,  14 
Erythrocytes,  118,  119 
Esophagus,  138 
Ethmoid  bone,  53 
Eustachian  tubes,  52,  63 

valve,  106,  107 


Excreting  glands,  35 
Extensor  carpi  radialis  longior, 

182,  183 

brevior,  182,  183 
ulnaris,  182,  183 
communis     digitorum,     182, 

184 

indicis,  182,  184 
minimi  digiti,  182,  184 
ossis  metacarpi  pollicis,  182, 

183 
primi  internodii  pollicis,  182, 

183 
secundi     internodii     pollicis, 

182,  183 
Eye,  66,  et  seq. 

accommodation,  72 

coats  of,  68 

color  of,  69 

formation    of    image  in,  70, 

et  seq. 

humors  of,  70 
muscles  of,  67 
nerves  of,  67,  68 
teeth,  60 
Eyeball,  66 
Eyebrows,  66 
Eyelashes,  67 
Eyelids,  66,  67 

FACE,  bones  of,  53,  et  seq. 
Facial  artery,  28 

nerve,  83,  84 
Fallopian  tubes,  166,  167 
Far-sightedness,  72,  73 
Fat  or  adipose  tissue,  16 
Fats,  12,  147,  148 

absorption,  144 

digestion,  143,  144 
False  pelvis,  163 

ribs,  97 
Fascia,  lumbar,  133 


INDEX. 


Fascia,  palmar,  184 

plantar,  198 
Fasciae,  15,  21 
Fasciculi,  21 
Fauces,  pillars  of,  59 
Feces,  146 
Female  generative  organs,  163, 

165,  et  seq. 

Femoral  artery,  190,  198 
Femur,  187 
Fenestra  ovalis,  63,  65 

rotunda,  65 
Ferments,  12,  136,  144 
Fetal  circulation,  106,  107 
Fetus,  111 
Fever,  45 
Fibrin,  11,23,33,117 

ferment,  117 
Fibrinogen,  117 
Fibrous  tissue,  15 
Fibula,  194,  195 
Fifth  nerve,  83 
Filum  terminale,  78,  91 
Fimbria?,  167 
First  nerve,  83 
Fissure  of  Rolando,  75,  82 

of  Sylvius,  75 

Flexor  carpi  radialis,  182,  183 
ulnaris,  182,  183 

longus  pollicis,  182,  183 

profundus  digitorum,  182, 183 

sublimis  digitorum,  182,  183 
Floating  ribs,  97 
Follicles,  Graafian,  166 
Fontanelles,   19,49 
Food,  147 

amount,  148 

classes  of,  147 

cooking,  148 

function,  147,  148 
Foot,  bones  of,  195,  196 

muscles  of,  198 


Foramen,  intervertebral,  90 

magnum,  50 

nutrient,  19 

obturator,  163 

of  Majendie,  79 

optic,  66,  70 

ovale,  106 
Foreign  bodies,  118,    122,    137, 

146 
Fossa,  coronoid,  175 

glenoid,  51 

iliac,   163 

nasal,  55,  57 

olecranon,  175 
Fourchette,  170 
Fourth  nerve,  68,  83 
Fovea  centralis,  70 
Fractures,  98,  164, 171, 174, 175, 

177,  180,  181,  193,  194,    195, 

196 

Frenum  of  tongue,  60 
Frontal  bone,  48,  49 

GALL-BLADDER  143,  152,  153 

stones,  143 
Ganglia,  87,  110 
Gangrene,  180,  199 
Gastric  artery,  109 

glands,  35 

juice,  139 

vein,  110,  150 
Gastrocnemius,  196 
Generative  organs,  female,  163, 

165,  et  seq. 
male,  163,  164,  165 
Genito-crural  nerve,  85 
Gladiolus  97 
Glands,  32,  35,  36 

ductless,  36 

excreting,  35 

functions,  36 

gastric,  35 


INDEX. 


209 


Glands,  lachrymal,  68 

lymphatic,  32,  34,  35 

mammary,  99,  100 

Meibomian,  67 

of  Lieberkuhn,  143,  144,  145 

parotid,  51,  62 

Peycr's,  142 

procreating,  165 

prostate,  164,  165 

racemose,  35 

salivary,  35,  61,  136 

sebaceous,  35,  40,  41 

secreting,  35 

solitary,  142,  145 

sublingual,  56,  62 

submaxillary,  56,  62 

sweat,  35,  42 

thymus,  124 

thyroid,  124 
Glenoid  cavity,  173 

fossa,  51 
Globulin,  11 
Glosso-pharyngeal    nerve,     61, 

84 

Glottis,  122,  129 
Gluteal  nerves,  199 
Glutei  muscles,  190 
Glycogen,  26,  36,  150,  151 
Goiter,  124 
Gonorrhea,  160,  168 
Graafian  follicles,  166 
Gray  matter  of  brain  and  cord, 

36,  75,  76,  78,  80,  81 
Green-stick  fracture,  19 
Groin,  glands  of,  32,  3~5 
Gustatory  cells,  61 

HAIR,  27,  40 

follicle,  40 
Hamstring,  inner,  191 

outer,  191 
Hard  palate,  55,  59 
14 


Haversian  canals,  17 
Hearing,  sense  of,  65 
Heart,  101,  el  seq. 

beat,  102,  104,  111,  112 

nerves,  110,  111 

position,  102 

sounds,  111 

structure,  103,  104 
Heat  center,  45 

production,  44 

prostration,  45 

stroke,  45 

Hemoglobin,  119,  130 
Hemorrhage,  139,  186 
Hemorrhoidal  veins,  146 
Hemorrhoids,  146 
Henle's  loops,  156 
Hepatic  artery,  109,  150 

duct,  143,  150 

flexure,  145,  146 

veins,  110 
Hernia,  146,  164 
Hiccough,  99,  131 
Highmore,  antrum  of,  54,  57 
Hilum  of  kidney,  155 
Hip  joint,  192 
Housemaid's  knee,  194 
Humerus,  175 
Humors  of  eye,  70 
Humpback  or  Pott's  disease,  91 
Hydrocarbons,  12 
Hydrocephalus,  34 
Hydrochloric  acid,  139,  140 
Hydrothorax,  34 
Hymen,  170 
Hyoid  bone,  60 

Hypermetropia   or  far-sighted- 
ness, 72,  73 

Hypochondriac  regions,  135 
Hypogastric  plexus,  87 

region,  135 
Hypoglossal  nerve,  84 


210 


INDEX. 


IDIOCY,  53 

Ileo-cecal  valve,  142,  145 
Ileo-pectineal  line,  163 
Ileum,  142 

Iliac  artery,  common,  107,  109 
deep  circumflex,  198 
external     and    internal, 

95,  109,  198 
fossae,  163 

Ilio-hypogastric  nerve,  85 
Ilio-inguinal  nerve,  85 
Ilium,  161,  162 
Impacted  hip,  193 
Incisor  teeth,  60 
Incus,  63 

Infundibula  of  lung,  125,  127 
Inguinal  regions,  135 
Innominate  artery,  107 
bone,  161,  162 
veins,  109 
Inorganic  compounds  in  body, 

12 
Intercostal  arteries,  95,  97,  100, 

108 

muscles,  98,  128 
nerves,  85,  97,  99,  134 
Intercellular  substance,  14,  17 
Interossei  muscles,  184 
Interosseous  nerves,  85,  186 
Internal  secretion,  36 
Intervertebral  foramen,  90 
Intestines,  141,  et  seq. 
large,  141,  145 
function,  146 
glands,  145 
nerves,  145 
structure,  145,  146 
small,  141,  142,  et  seq. 
blood-vessels,  143 
function,  143,  144 
glands,  142,  143 
nerves,  143 


Intestines,  small,  structure,  142 
Intima,  27 

Intralobular  vein,  150 
Intussusception,  146 
Involuntary  muscle,  21 
Iris,  68,  69,  72 
Ischium,  161,  103 
Island  of  Reil,  75 

JAUNDICE,  35,  152,  153,  158 
Jejunum,  142 
Joints,  15,  20 

classes  of,  20,  21 

ankle,  195 

elbow,  21,  185, 

hip,  21,  192 

knee,  193 

motion  of,  20,  21 

shoulder,  21,  185 

wrist,  185 
Jugular  veins,  109 
Juice,  gastric,  139 

pancreatic,  143,  144,  153 

KATABOLISM,  147 
Kidneys,  155,  et  seq. 

floating,  159 

function,  156,  et  seq. 

position,  155 

structure,  155,  156, 
Knee-jerk,  83 
Knee  joint,  193 

LABI  A  majora,  169 

minora  or  nympha?,  170 
Labyrinth,  membranous,  64,  65 

osseous,  64 
Lachrymal  bones,  48,  54 

canal,  54,  57 

duct,  68 

gland,  68 

sac,  54,  68 


INDEX. 


211 


Lacteals,  32,  144 
Lacunae  of  bone,  17 
Lambdoidal  suture,  48 
Lamellae  of  bone,  17 
Laminae  of  vertebrae,  89 
Large  intestine,  141,  145 
Laryngitis,  122 
Laryngotomy,  122 
Larynx,  -121 
Latissimus  dorsi,  93 
Laughing,  131 
Lens,  crystalline,  69,  70 
Leucocytes,  33,  34,  119,  120 
Levator  scapulae,  93 
Levatores  of  ribs,  129 
Lieberkiihn,  glands  of,  143,  144, 

145 
Ligaments,  15,  20,  21 

annular,  184,  198 

broad,  of  uterus,     165,     166, 
168 

capsular,  of  hip,  21,  193 

crucial,  of  knee,  193 

orbicular,  178 

Poupart's,  132 

round,  of  uterus,  168 

suspensory,  of  liver,  149 

thyro-arytenoid,  122 
Ligamentum    nuchae,    50,     91, 
93 

patellae,  190,  192,  193,  194 

teres,  187 

Line,  Nelaton's,  189 
Linea  alba,  132 

aspera,  187 
Liver,  36,  149,  et  seq. 

blood-supply,  150 

diseases  of,  152 

function,  150,  et  seq. 

position,  149 

structure,  149,  150 
Loops  of  Henle,  156 


Lower  extremities,  187,  et  seq. 
Lumbar  artery,  95,  109 

fascia,  133 

nerves,  84,  85 

plexus,  84 

regions,  135 

vertebrae,  90 
Lumbricales,  184 
Lungs,  125,  et  seq. 

function,  127,  et  seq. 

nerves,  127 

position,  126 

structure,  126,  127 
Lupus,  58 
Lymph,  30,  32 

capillaries,  30 

character,  32,  33 

flow  of,  33 

function,  34 

spaces,  30 

transudation  of,  33 
Lymphatic  glands,  32,  34,  35 

system,  27,  29,  et  seq. 

vessels,  30,  31 

valves  of,  31,  32,  33 

MACULA  lutea,  70 

Malar  or  cheek  bone,  48,  54 

Malaria,  154 

Male  organs  of  generation,  163, 

164,  165 
Malleolus  of  fibula,  194,  195 

of  tibia,  194 
Malleus,  63 
Malpighian  bodies,  156 

pyramids,  156 

Mammary  artery,  internal,  99, 
100,  108 

glands,  99,  100 
Manubrium,  97 
Marrow  of  bone,  18 
Masseter,    51,  54 


212 


INDEX. 


Mastoid  abscess,  51,  52 

cells,  51,  <il 

portion  of  temporal  bone,  51 
Maxillary  bone,  inferior,  48,  55 

superior,  48,  54 
Me  Burney's  point,  145 
Meatus,  auditory,  52,  65 

nasal,  57 

urinarius,  160,  165,  170 
Median,  cephalic  vein,  109 

nerve,  85,  186 

vein,  109 

Mediastinal  artery,  99 
Mediastinum,  32,  126 
Medulla  or  marrow,  18 
Medulla  oblongata,  78,  79,  82 
Medullary  artery,  19 

canal,  19 

sheath,  37 
Meibomian  duct,  74 

glands,  67 

Membrana  tympani  or  drum,  63 
Membranous  labyrinth,  64,  65 
Mesenteric   arteries,    109,    143, 
145,  153 

veins,  110,  150 
Mesenteries,  32  134 
Metabolism,  45,  147,  151,  152 
Metacarpal  bones,  181 
Metatarsal  bones,  195 
Micturition,  157 
Milk  teeth,  60 
Mitral  valve,  104 
Molar  teeth,  60 
Monometer,  114 
Mons  Veneris,  169 
Motor  areas,  81,  82 

center,  81,  82 

oculi  nerve,  68,  83 

tract,  82 

Mouth,  59,  et  seq. 
Mucous  membrane,  40 


Mucus,  40 
Mumps,  62 
Muscle,  21,  et  seq. 

action,  23,  24 

cardiac,  22,  25 

characteristics,  22,  23,  24,  25 

classes  of,  21 

fatigue  of,  26,  27 

function  of,  24 

smooth,  21,  25 

sounds,  25 

striated,  21,  23,  25 

work,  25,  26 
Muscles  of  abdomen,  132,  et  seq. 

of  arm,  175,  176,  177 

of  back,  93,  94 

of  chest,  98,  99,  128 

of  foot,  198 

of  forearm,  182 

of  hand,  184 

of  head,  50,    51,    54,    55,    58, 
67,  69 

of  leg,  196,  et  ssq. 

of  neck,  51,  92,  93,  129 

of  shoulder,  174 

of  thigh,  189,  et  seq. 
Musculo-cutaneous    nerve,    85, 

186,  199 
Musculo-spiral  nerve,  85,  175, 

186 

Musical  sounds,  65 
Myopia  or  near-sightedness,  72, 

73 

Myosin,  11,  23 
Myosinogen,  23 

NAILS,  27,  40 
Nares,  57 
Nasal  bones,  55 

duct,  68 

fossae,  55,  57 

meatus,  57 


INDEX. 


213 


Nasal  septum,  55 
Navicular  or  scaphoid  bone,  195 
Near-sightedness,  72,  73 
Neck,  glands  of,  32 

muscles  of,  51,  1)2 
Nekton's  line,  189 
Nerve,  37 

action  of,  37,  38,  83 

cell  or  gray  matter,  36 

fiber  or  white  matter,  36 

function,  37 

ganglia,  87,  110 

motor,  82 

plexus,  29,  84,  et  seq. 

sensory,  82,  83 

terminations,  37 
Nerves,  24,  36 

abducens,  83 

auditory,  64,  65,  84 

cardiac,  78 

cervical,  84 

circumflex,  85,  186 

coccygeal,  84 

cranial,  77,  78,  83,  84 

crural,  anterior,  85,  199 

cutaneous,  46,  85 

dorsal  or  thoracic,  84,  85 

eighth,  64,  84 

eleventh,  84 

facial,  83 

fifth,  83 

first,  83 

fourth,  68,  83 

genito-crural,  85 

glosso-pharyngeal,  61,  84 

gluteal,  199 

hypoglossal,  84 

ilio-hypogastric,  61,  85 

ilio-inguinal,  85 

intercostal,  85,  97,  99,  134 

interosseous,  85,  186 

lumbar,  84,  85 


Nerves,  median,  85,  186 
motor  oculi,  68,  83 
musculo-cutaneous,   85,   186, 

199 

musculo-spiral,  85,  175,  186 
ninth,  84 
obturator,  85 
olfactory,  53,  58,  83 
optic,  70,  71,  76,  83 
patheticus,  83 
phrenic,  85,  99,  130 
plantar,  85 
pneumogastric,  84,  110,    111, 

127,  130,  153 
popliteal,  85,  199 
post-tibial,  85 
radial,  85 
sacral,  84 

sciatic,  85,  163,  199 
second,  70,  83 
seventh,  83 
sixth,  68,  83 
spinal,  84,  95 

accessory,  84,  95,  137 
suprascapular,  186 
sympathetic,  87, 110, 127, 137, 

143,  145,  168 
tenth,  84 
third,  68,  -72,  83 
thoracic,  186 

cutaneous,  100 
tibial,  86,  87,  199 
trifacial,  61,  83 
twelfth,  84 
ulnar,  85,  175,  186 
vagus,  84,  110,  111,  127,130, 

153 
vasoconstrictors,  115 

dilators,  115 

motor,  29,  78,  115 
Nervous  system,  38,  75,  et  seq. 
tissue,  13,  36 


214 


INDEX. 


Neurilemma,  37 
Ninth  nerve,  84 
Nipple,  100 
Nose,  57,  58 
bleed,  59 
Nucleolus,  12 
Nucleus,  12 
Nutrient  foramen,  19 
Nymphae,  170 

OBLIQUE  muscles  of  abdomen, 

132 

of  eye,  68 
Obturator  foramen,  163 

nerve,  85 

Occipital  bone,  48,  50 
Occipito-frontalis  muscle,  51 
Odontoid  process  of  axis,  91 
Olecranon  fossa,  175 

process,  178 
Olfactory  bulbs,  53,  58,  76 

cells,  58 

grooves,  53 

nerves,  53,  58,  83 

tract,  58,  76 
Omenta,  134,  146 
Ophthalmic  artery,  70 
Optic  axis,  70 

commissure,  76 

foramen,  66,  70 

nerve,  70,  71,  76,  83 

tract,  76 

Orbicular  ligament,  178 
Orbicularis  palpebrarum,  67 
Orbit  of  eye,  54,  66 
Organ  of  Corti,  65 
Organic  compounds  in  body,  11, 

12 
Os  calcis,  195 

innominatum,  161,  162 

magnum,  181 

uteri,  168 


Osseous  labyrinth,  64 
Ossicles  of  ear,  63,  65 
Osteoblasts,  18 
Osteomalacia,  164,  189 
Osteomyelitis,  193 
Oval  window,  63,  64,  65 
Ovaries,  165 
Ovum,  12,  166,  168 
Oxyhemoglobin,  130 

FACET'S  disease,  53 
Pain,  sensation  of,  47,  81 
Palate,  bones  of,  48,  54 

cleft,  55 

hard,  55,  59 

soft,  59,  60,  136 
Palmar,  arch,  186 

fascia,  184 

Palmaris  longus,  182,  183 
Pancreas,  153 
Pancreatic  duct,  143,  153 

juice,  143,  144,  153 
Pancreatitis,  153 
Panhysterectomy,  169 
Papillae  of  skin,  37,  39 

of  tongue,  61 
Paralysis,  79 
Parietal  bone,  48,  49 
Parotid  gland,  51,  62 
Patella  or  knee-cap,  19,  192 
Patheticus  nerve,  83 
Pectoral  muscles,  99,  128 
Pectoralis  major,  174 
Pedicles  of  vertebrae,  89 
Pelvis,  132,  161,  et  seq. 

false,  163 

of  kidney,  156 

true,  163,  164 
Penis,  160,  165 
Pepsin,  140 
Peptones,  12,  140,  150 
Pericardium,  34,  101,  102 


INDEX. 


215 


Perichondrium,  16 
Perineal  body,  170 
Perineum,  170 
Perilymph,  64,  65 
Periosteum,  15,  18,  19,  76 
Peripheral  resistance,  112,  114 
Peristaltic  movements,  138,143, 

146 

Peritoneum,  134 
Permanent  teeth,  60 
Peroneal  artery,  199 
Peroneus  brevis,  197 

longus,  197 
Petrous    portion    of    temporal 

bone,  51,  52 

Peyer's  patches  or  glands,  142 
Phalanges  of  foot,  195 

of  hand,  181 
Pharynx,  59,  136,  137 
Physiology,  11 
Phrenic  artery,  99,  109 

nerve,  85,  99,  130 
Pia  mater,  76 
Pigeon  breast,  97 
Pillars  of  the  fauces,  59,  60 
Pink  eye,  74 
Pinna,  63 
Pisiform  bone,  181 
Pituitary  body,  36 
Placenta,  106,  107 
Plantar  artery,  199 

fascia,  198 

nerve,  86 
Plantaris,  197 

Plasma  of  blood,  33,  116,  117 
Platysma  myoides,  92 
Pleurae,  34,  125 
Plexus,  29 

brachial,  84,  85 

cardiac,  87 

cervical,  84 

hypogastric,  87 


Plexus,  lumbar,  84 

sacral,  84,  85 

solar,  87,  153 
Pneumogastric   nerve,  84,  110, 

127,  153 
Polypi,  58 
Pons  Varolii,  78 
Popliteal  artery,  198 

nerves,  86,  199 

space,  32,  198 
Popliteus  muscle,  198 
Portal  circulation,  110 

vein,  110,  150 
Pott's  disease,  91 

fracture,  180,  195 
Poupart's  ligament,  132 
Prepatella  bursa,  192 
Prepuce,  165 
Presbyopia,  73 
Presternal  notch,  171 
Procreating  glands,  165 
Profunda  artery,  175,  186 

femoris  artery,  198 
Promontory  of  the  sacrum,  90 
Pronator  quadratus,  182,  183 

radii  teres,  182,  183 
Prostate  gland,  164,  165 
Proteins,  11,   26,   33,    140,  144, 

147,  148 

Protoplasm,  12,  13 
Psoas  magnus,  189,  190 

parvus,  190 
Ptosis  of  liver,  152 

of  upper  lid,  74 
Ptyalin,  61,  136 
Pubes,  161,  163 
Pudic  artery,  168 
Pulmonary  artery,  106,  110 

circulation,  110 

valves,  104 

veins,  105,  110 
Pulse,  112,  113,  114,  115 


216 


INDEX. 


Pulse,  causes,  112 

dicrotic,  113 

rate,  111,  113,  114 
Pupil  of  eye,  69,  72 
Pus  corpuscles,  120 
Pylorus,  138 
Pyramidalis  muscle,  134 
Pyramids,  Malpighian,  156 

QUADRATUS  lumborum,  134 
Quadriceps  extensor,  190 

RADIAL  artery,  108,  185 

nerve,  85 

Racemose  glands,  35 
Radius,  178,  179 
Rales,  129 

Receptaculum  chyli,  32 
Recti  muscles  of  eye,  67,  72 
Rectum,  145,  146 
Rectus  abdominis,  133,  134 

capitis  anticus  major,  93 

femoris,  190 

Red  corpuscles,  118,  119 
Reflex  action,  83 
Regions,  abdominal,  134,  135 
Renal  artery,  109 
Rennin,  140 
Respiration,  121,  127,  et  seq. 

center  of,  78,  130 

effect  on  air,  129,  130 

effect  on  blood,  130,  131 

forced,  128,  129 

kinds  of,  128 

rate,  128 

sounds,  129 

variations  in,  131 
Retching,  140 
Retina,  68,  69,  70 
Rheumatism,  25 
Rhomboideus  muscles,  93 
Rickets,  19,  49,  53,  97,  164, 195 


Ribs,  97,  9S 

Right  lymphatic  duct,  31,  32 

Rigor  mortis,  22,,  23 

Rivinus,  ducts  of,  62 

Rodent  ulcer,  74 

Rods  and  cones,  69,  70 

Rolando,  fissure  of,  75,  82 

Rosary,  97 

Round  ligament  of  uterus,  168 

Round  window,  64,  65 

Rupture,  146,  164 

of  kidney,  158 

of  liver,  152 

of  spleen,  154 

of  urethra,  160 

SACRAL  nerves,  84 

plexus,  84,  85 

vertebrae,  90 
Sacro-sciatic  notch,  163 
Sacrum,  90,  161 
Sagittal  suture,  48 
Saliva,  61,  136 
Salivary  glands,  35,  61,  136 
Salpingectomy,  169 
Saphenous  veins,  109,  199 
Sarcolemma,  21 
Sarcoma,  173,  177,  11)3 
Sartorius  muscles,  23,  190 
Scalenus  muscles,  93,  128 
Scaphoid  bone,  ankle,  195 

wrist,  181 
Scapula,  173 
Scarlet  fever,  35 
Scarpa's  triangle,  190,  198 
Schwann,   white  substance   of, 

37 

Sciatic  nerve,  85,  163,  199 
Sclera  or  sclerotic  coat,  68 
Scrotum,  165 

Sebaceous  glands,  35,  40,  41 
Sebum,  41 


INDEX. 


217 


Second  nerve,  70,  83 
Secreting  glands,  35 
Segmentation,  growth  by,  12 
Semen,  165 

Semicircular  canals,  64,  66 
Semilunar  bones,  181 

cartilages,  193,  194 

valves,  28,  32,  104 
Semimembranosus  muscle,  191 
Semitendinosus  muscle,  191 
Sense,  organs  of,  57,  et  seq. 

of  hearing,  65 

of  sight,  70,  et  seq. 

of  smell,  55,  57,  58,  61 

of  taste,  55,  61 

of  touch,  45,  et  seq. 
Sensory  nerves,  82,  83 

tract,  82 
Septum  of  nose,  55 

deviation  of,  58 
Serous  membrane,  40 
Serratus  rnagnus,  174 
Serum  albumin,  1 1 

of  blood,  117 
Sesamoid  bones,  19 
Seventh  nerve,  83 
Shin,  194 
Shoulder  girdle,  171 

joint,  185 
Sighing,  131 

Sight,  sense  of,  70,  et  seq. 
Sigmoid  cavities,  178 

flexure,  145,  146 
Silent  areas  in  brain,  82 
Silver  fork  deformity,  180 
Sinuses,  28,  49,  51,  52,  78,  105 
Sixth  nerve,  68,  83 
Skin,  39,  et  seq. 
Skull,  bones  of,  48,  et  seq. 
Small  intestine,  141,  142,  et  seq. 
Smell,  sense  of,  55,  57,  58,  61 
Smooth  muscle,  21,  25 


Sneezing,  131 

Sobbing,  131 

Soft  palate,  59,  60,  136 

Solar  plexus,  87,  153 

Soleus,  196 

Solitary  glands,  142,  145 

Sounds,  65,  66 

Special  senses,  57,  et  seq. 

Speech,  122 

center,  82 

Spermatic    or    ovarian    artery, 
109,  168 

cords,  165 
Spermatozoa,  165 
Sphenoid  bone,  48,  52 
Sphincter  of  anus,  146 

of  pupil,  72 

of  pylorus,  138 
Spina  bifida,  91 

Spinal  accessory  nerve,  84,  95, 
137 

canal,  91 

column,  88 

cord,  79,  et  seq. 

foramen,  89 

nerves,  84,  95 
Spine,  87 
Spinous    process    of    vertebrae, 

89 

Spleen,  153,  154 
Splenic  artery,  109,  153 

flexure,  145,  146 

vein,  110,  150 
Sprain,  21 
Squamous  portion  of  temporal 

bone,  51 
Stapes,  63 

Starches,  12,  136,  144 
Steapsin,  144 
Stensen's  duct,  62 
Sterno-cleido-mastoid     muscle, 

51,  92,  171 


218 


INDEX. 


Sternum,  97 
Stimuli,  24 
Stomach,  138 

arteries,  139 

digestion  in>  139,  140 

glands,  139 

position,  138 

structure,  139 
Stomach  teeth,  60 
Strabismus,  72 
Striated  or  striped  muscle,  21, 

23,  25 
Stricture  of  esophagus,  138 

of  urethra,  160 
Sty,  74 

Styloid  process  of  fibula,  195 
of  radius,  178,  179 
of  temporal  bone,  52 
of  ulna,  178,  179 
Subarachnoid  space,  76,  79 
Subclavian  arteries,  94,  9'),  107, 

108,  185 

veins,  109 

Subclavius  muscle,  173 
Subdural  space,  76 
Sublingual  gland,  56,  62 
Submaxillary  gland,  56,  62 
Succus  entericus,  143,  144 
Sugar  in  urine,  151,  158 
Superciliary  ridges,  49 
Supinator  brevis,  182,  184 

longus,  182,  184 
Supraorbital  foramen  or  notch, 
49 

vessels  and  nerve,  49 
Suprarenal  artery,  109 

capsules,  36,  154 
Suprascapular  artery,  94 

nerve,  186 
Suspensory  ligament  of  lens,  70, 

72 
of  liver,  149 


Sutures,  48,  53 

coronal,  48 

lambdoidal,  48 

sagittal,  48 
Sweat,  composition,  42 

functions,  42 

glands,  35,  42 

nervous  control  of,  42 

quantity,  43 
Sylvius,  fissure  of,  75 
Sympathetic  nerve,  87,  110, 
127,  137,  143,  145,  168 

system,  75,  87 
Symphysis  pubis,  163 
Synovial  fluid,  20,  34 

membrane,  20 
Syphilis,  35,  58,  122,  152,  182, 

194 
Systemic  circulation,   105,   106, 

107,  et  seq.,  112,  113 
Systole,  104,  106,  112 

T-FRACTURE,  177,  193 
Tablets  of  skull,  20,  48 
Tactile  corpuscles,  37,  39,  46 
Tarsus  or  ankle,  195 
Taste  buds,  61 

nerves  of,  61 

sense  of,  55,  61 
Tears,  68 
Teeth,  27,  60 
Temperature  of  body,  43 

regulation  of,  43 

sensation  of,  47 

variations  in,  44 
Temporal  bone,  48,  51 

muscle,  50,  51,  55 
Temporary  or  milk  teeth,  60 
Tendo  Achillis,  195,  197 
Tendons,  15,  23 
Tenth  nerve,  84 
Testes  or  testicles,  165 


INDEX. 


210 


Third  nerve,  68,  72,  83 
Thoracic  aorta,  99,  107,  109 

duct,  31 

nerves,  186 

Thoracic  cutaneous  nerve,  100 
Thorax,  96 

Thymus  gland,  36,  124 
Thyro-arytenoid  ligaments,  122 
Thyroid  axis,  108 

cartilage,  121 

gland,  36,  124 
Tibia  or  shin  bone,  194 
Tibial  artery,  198 

nerve,  76,  87,  199 
Tibialis  anticus,  197 
Tissues,  areolar,  15 

bony,  13,  17 

cartilaginous,  13 

connective,  13,  15 

differentiation  of,  13 

elastic,  15 

epithelial,  13 

fibrous,  15 

muscular,  13 

nervous,  13,  36 
Tongue,  46,  59,  60 

tie,  62 

Tonsillitis,  35,  62 
Tonsils,  59,  62 
Torticollis,  92 
Touch,  corpuscles,  37,  39,  46 

sense  of,  45,  et  seq. 
Trachea,  123 
Tracheotomy,  123 
Transudation  of  lymph,  33 
Transversalis  muscle,  133 

colli  artery,  94 
Transverse  colon,  145 

processes  of  vertebrae,  89 
Trapezium,  181 
Trapezius,  93,  171 
Trapezoid  bone,  181 


Triangular  cartilage,  57 
Triceps,  176,  177 
Tricuspid  valve,  104 
Trifacial  nerve,  61,  83 
Trochanters,  189 
Trochlear  surface  of  femur, 

189 

of  humerus,  175 
True  pelvis,  163,  164 

ribs,  97 
Trypsin,  144 
Tuberculosis,  35,  122,  155,  159, 

168,  182,  193,  194,  196 
Tuberosities  of  humerus,  175 

of  tibia,  194 
Tuberosity  of  ischium,  163 

of  radius,  178 
Tubuli  lactiferi,  100 
Tumor  albus,  194 
Tumors,  100,  175 
Tunica  vaginalis  oculi,  67 
Turbinated  bones,  48,  53,  54 
Twelfth  nerve,  84 
Tympanum,  51,  63 
Typhoid  fever,  142,  154 

ULCER,  139 

Ulna,  177,  178,  185 

Ulnar  artery,  108 

nerve,  85,  175,  186 
Umbilical  artery,  107 

region,  135 

vein,  106 

Unciform  bone,  181 
Unstriated  or  unstriped  muscle, 

21,  22,  25 

Upper  extremities,  171,  et  seq. 
Urea,  148,  152,  158 
Ureters,  155,  156,  159 
Urethra,  159,  160,  165 
Urinary  apparatus,  155,  et  seq. 
Urine,  156,  et  seq. 


220 


INDEX. 


Uterine  artery,  168 
Uterus,  167,  168 
Uvula,  59 

VAGINA,  168 

Vagus  or  pneumogastric  nerves, 

84,  110,  111,  130 
Valves,  103 

aortic,  104 

bicuspid  or  mitral,  104 

coronary,  105 

Eustachian,  106,  107 

ileo-cecal,  142,  145 

of  lymphatic  vessels,   31,   32, 
33 

of  veins,  28 

pulmonary,  104 

semilunar,  28,  32,  104 

tricuspid,  104 
Valvulse  conniventes,  142 
Varicose  veins,  109,  113,  199 
Vas  deferens,  165 
Vasa  nervorum,  37 

vasorum,  29 
Vasoconstrictor  nerves,  115 

dilator  nerves,  115 

motor  nerves,  29,  78,  115 
Vascular  system,  107.  et  seq. 
Vastus  externus,  190 

internus,  190 
Veins,  27,  28,  29,  109 

basilic,  109 

deep,  28 

gastric,  110,  150 

hemorrhoidal,  146 

hepatic,  110,  150 

iliac,  common,  109 

inferior  vena  cava,  105,  109, 
150 

innominate,  109 

intralobular,  150 

jugular,  109 


Veins,  median,  109 
cephalic,  109 

mesenteric,  110,  150 

portal,  110,  150 

pulmonary,  105,  110 

saphenous,  109,  199 

splenic,  110,  150 

subclavian,  109 

superficial,  28 

superior  vena  cava,  105,  109 

umbilical,  106 

valves,  28 

varicosity,  109,  113,  199 
Vena  cava,  inferior,    105,    109, 

150 

superior,  105,  109 
Venae  comites,  27,  113 
Ventricles  of  brain,  75,  79 

of  heart,  103 

Vermiform  appendix,  145 
Vertebra  prominens,  91 
Vertebras,  88,  et  seq. 
Vertebral  arteries,  77 
Vesiculae  seminales,  165 
Vestibule  of  labyrinth,  64,  65 
Vicarious    function    of   glands, 

35 

Villi,  142 

Viscera,  abdominal,  135,  et  seq. 
Visual  center,  81 
Vital  capacity,  129 
Vitreous  humor,  70 
Vocal  cords,  122 
Volvulus,  146 
Voluntary  muscle,  21,  23 
Vomer,  48,  55 
Vomiting,  140 
Vulva,  169 

WHARTON'S  duct,  62 
White  corpuscles  or  leucocytes, 
27,33,34,119,120 


INDEX.  221 

White   substance   of   Schwann,  Wrist,  180 

37  joint,  185 

matter  of  brain  and  cord,  75,  Wry  neck  or  torticollis,  92 

76,  78,  80,  81  YAWNING,  131 
Willis,  circle  of,  78,  108 

Wisdom  teeth,  60  ZYGOMATIC  process  of  temporal 

\\ormian  bones,  19,  49  bone,  51,  54 


SAUNDERS'    BOOKS 
FOR   NURSES 

PAGE 

Aikens'  Clinical  Studies  for  Nurses 3 

Aikens'  Hospital  Management 3 

Aikens'  Primary  Studies  for  Nurses 3 

Aikens'  Training  School  Methods  and  the  Head  Nurse  .  3 

Beck's  Reference  Handbook  for  Nurses 4 

Boyd's  State  Registration  for  Nurses ...  4 

Davis'  Obstetric  and  Gynecologic  Nursing 5 

DeLee's  Obstetrics  for  Nurses 5 

Borland's  Medical  Dictionaries 7,  8 

Fiske's  Anatomy  and  Physiology  for  Nurses 4 

Fowler's  Operating  Room  and  the  Patient  ...         .    .  4 

Friedenwald  and  Ruhrah  on  Diet 6 

Galbraith's  Four  Epoch's  of  Woman's  Life 6 

Galbraith's  Hygiene  and  Physical  Training  for  Women  6 

Grafstrorn's  Mechanotherapy  (Massage) 8 

Griffith's  Care  of  the  Baby 8 

Hoxie's  Medicine  for  Nurses 8 

Lewis'  Anatomy  and  Physiology  for  Nurses 

Macfarlane's  Gynecology  for  Nurses 5 

Manhattan  Hospital  Eye,  Ear,  Nose  and  Throat  Nursing  6 

McCombs'  Diseases  of  Children  for  Nurses 7 

McKenzie's  Exercise  in  Education  and  Medicine  ....  5 

Morris'  Essentials  of  Materia  Medica 8 

Morrow's  Immediate  Care  of  Injured 8 

Nancrede's  Essentials  of  Anatomy 8 

Paul's  Materia  Medica  for  Nurses 8 

Paul's  Nursing  in  the  Acute  Infectious  Fevers  =    .    .    .    .  8 

Pyle's  Personal  Hygiene 8 

Register's  Fever  Nursing 8 

Stoney's  Bacteriology  and  Surgical  Technic 2 

Stoney's  Materia  "Medica  for  Nurses 2 

Stoney's  Nursing 2 

Wilson's  Reference  Handbook  of  Obstetric  Nursing    .    .  7 

W.    B.    SAUNDERS     COMPANY 

925  Walnut  Street  Philadelphia 

London:    9,  Henrietta  Street,  Covent   Garden 


Stoney's    Nursing 


NEW  (4th)   EDITION 

In  this  excellent  volume  the  author  explains  the  entire  range 
of  private  nursing  as  distinguished  from  hospital  nursing; 
and  the  nurse  is  given  definite  directions  how  best  to  meet  the 
various  emergencies.  The  American  Journal  of  Nursing  says 
it  "is  the  fullest  and  most  complete' '  and  ' '  may  well  be  rec- 
ommended as  being  of  great  general  usefulness.  The  best 
chapter  is  the  one  on  observation  of  symptoms  which  is  very 
thorough. ' '  There  are  directions  how  to  improvise  everything 
ordinarily  needed  in  the  sick  room. 

Practical  Points  in  Nursing.  By  EMILY  M.  A.  STONEY,  Superin- 
tendent of  the  Training  School  for  Nurses  in  the  Carney  Hospital, 
South  Boston,  Mass.  12010,  495  pages,  illustrated.  Cloth,  $1.75  net. 


Stoney's  Materia  Medica 


NEW  (3d)  EDITION 


Stoney's  Materia  Medica  was  written  by  a  head  nurse  who 
knows  just  what  the  nurse  needs.  American  Medicine  says 
it  contains  "all  the  information  in  regards  to  drugs  that  a 
nurse  should  possess.  *  *  *  The  treatment  of  poisoning 
is  stated  in  a  manner  that  will  permit  of  its  being  carried  out 
thoroughly  and  intelligently. ' ' 

Materia  Medica  for  Nurses.  By  EMILY  M.  A.  STONEY,  Superin- 
tendent of  the  Training  School  for  Nurses  in  the  Carney  Hospital, 
South  Boston,  Mass.  i2mo  volume  of  300  pages.  Cloth,  $1.50  net. 


Stoney's  Surgical  Technic 


NEW    (3d)    EDITION 


The  first  part  of  the  book  is  devoted  to  Bacteriology  and 
Antiseptics;  the  second  part  to  Surgical  Technic,  Signs  of 
Death,  Autopsies,  Bandaging  and  Dressings,  Obstetric  Nurs- 
ing, Care  of  Infants,  etc.,  Hygiene  and  Personal  Conduct  of 
the  Nurse,  etc.  The  New  York  Medical  Record  says  it  "  is  a 
very  practical  book  which  presents  the  subjects  stated  in  its 
title  in  a  concise  manner." 

Bacteriology  and  Surgical  Technic  for  Nurses.  By  EMILY  M.  A. 
STONEY.  Revised  by  FREDERIC  R.  GRIFFITH,  M.  D.,  New  York 
i2mo  volume  of  300  pages,  fully  illustrated.  Cloth,  $1.50  net. 


Aikens'    Hospital  Management         REJADY 

This  is  just  the  work  for  hospital  superintendents,  training- 
school  principals,  physicians,  and  all  who  are  actively  inter- 
ested in  hospital  administration.  Each  chapter  has  been 
written  by  one  specially  fitted  to  write  upon  that  particular 
phase  of  the  subject ;  and  Miss  Aikens  has  brought  the 
various  chapters  into  a  harmonious  whole. 

Hospital  Management.  Arranged  and  edited  by  CHARLOTTE  A. 
AlKENS,  formerly  Director  of  Sibley  Memorial  Hospital,  Washing- 
ton, D.  C.  12010  of  488  pages,  illustrated.  Cloth,  $3.00  net 

Aikens'  Primary  Studies  for  Nurses 

Trained  Nurse  and  Hospital  Review  says:  "It  is  safe  to  say 
that  any  pupil  who  has  mastered  even  the  major  portion  of 
this  work  would  be  one  of  the  best  prepared  first  year  pupils 
who  ever  stood  for  examination." 

Primary  Studies  for  Nurses,  By  CHARLOTTE  A.  AlKENS,  formerly 
Director  of  Sibley  Memorial  Hospital,  Washington,  D.  C.  xarno  of 
435  pages,  illustrated.  Cloth,  $1.75  net. 

Aikens'  Training-School  Methods  and 
the  Head  Nurse 

This  work  not  only  tells  how  to  teach,  but  also  what  should 
be  taught  the  nurse  and  how  much.  The  Medical  Record  says: 
"  This  book  is  original,  breezy  and  healthy." 

Hospital  Training-School  Methods  and  the  Head  Nurse.  By  CHAR- 
LOTTE A.  AlKENS,  formerly  Director  of  Sibley  Memorial  Hospital, 
Washington,  D.  C.  i2mc  of  267  pages.  Cloth,  $1.50  net 

Aikens'    Clinical    Studies    for    Nurses 

ILLUSTRATED 

This  new  work  is  written  on  the  same  lines  as  the  author's 
successful  work  for  primary  students,  taking  up  the  studies 
the  nurse  must  pursue  during  the  second  and  third  years. 

Clinical  Studies  for  Nurses.  By  CHARLOTTE  A.  AIKENS,  formerly 
Director  of  Sibley  Memorial  Hospital,  Washington,  D.  C.  izrao  of 
512  pages,  illustrated.  Cloth,  $2.00  net. 


Fowler's  Operating  Room        NEW  (2d)  EDITION 

Dr.  Fowler's  work  contains  all  information  of  a  surgical 
nature  that  a  nurse  must  know  in  order  to  attain  the  highest 
efficiency.  Canadian  Journal  of  Medicine  and  Surgery  says : 
"We  find  compactly  and  clearly  stated  just  those  thousand 
and  one  things  which  when  required  are  so  hard  to  locate." 

The  Operating  Room  and  the  Patient.  By  RUSSELL  S.  FOWLER. 
M.  D.,  Professor  of  Surgery,  Brooklyn  Postgraduate  Medical  School. 
Octavo  of  284  pages,  with  original  illust  tions.  Cloth,  $2.00  net. 


JUST 
READY 


Fiske's  Anatomy  and  Physiology 

Miss  Fiske  weaves  the  physiology  in  with  the  anatomy,  and 
in  such  a  way  that  both  anatomy  and  function  are  readily 
understood  and  retained  by  the  reader. 

Anatomy  and  Physiology  for  Nurses.  By  ANNETTE  FISKE,  A.M., 
Graduate  of  the  Waltham  Training  School  for  Nurses,  Massa- 
chusetts. i2mo  of  250  pages,  illustrated. 


Beck's  Reference  Handbook 


NEW  (2d)  EDITION 


This  book  contains  all  the  information  that  a  nurse  requires 
to  carry  out  any  directions  given  by  the  physician.  The 
Montreal  Medical  Journal  says  it  is  ' '  cleverly  systematized  and 
shows  close  observation  of  the  sickroom  and  hospital  regime." 

A  Reference  Handbook  for  Nurses.  By  AMANDA  K.  BECK,  Grad- 
uate of  the  Illinois  Training  School  for  Nurses,  Chicago,  111. 
321110  volume  of  200  pages.  Bound  in  flexible  leather,  $1.25  net. 

Boyd's  State  Registration  for  Nurses 

This  book  tells  the  nurse  just  what  she  must  know  in  order  to 
obtain  a  certificate  in  any  State.  It  presents  comparative 
summaries  of  the  laws,  requirements,  fees,  exceptions  and 
restrictions,  violations  and  their  penalties.  The  work  will 
also  form  a  serviceable  basis  for  the  drafting  of  laws. 

State  Registration  for  Nurses.  By  LOUIE  CROFT  BOYD,  R.N.,  Grad- 
uate Colorado  Training  School  for  Nurses.  Price,  50  cents  net. 


DeLee's  Obstetrics  for  Nurses 

Dr.  DeL,ee's  book  really  considers  two  subjects — obstetrics 
for  nurses  and  actual  obstetric  nursing.  Trained  Nurse  and 
Hospital  Review  says  the  "book  abounds  with  practical 
suggestions,  and  they  are  given  with  such  clearness  that 
they  cannot  fail  to  leave  their  impress." 

Obstetrics  for  Nurses.  By  JOSEPH  B.  DELEE.  M.  D.,  Professor  of 
Obstetrics  at  the  Northwestern  University  Medical  School,  Chicago. 
izmo  volume  of  512  pa^es,  fully  illustrated.  Cloth,  $2.50  net. 

Davis'  Obstetric  &  Gynecologic  Nursing 

THE   NEW  (3d)  EDITION 

The  Trained  Nurse  and  Hospital  Review  says:  *  *  This  is  one 
of  the  most  practical  and  useful  books  ever  presented  to  the 
nursing  profession."  The  text  is  illustrated. 

Obstetric  and  Gynecologic  Nursing.  By  EDWARD  P.  DAVIS,  M.  D.. 
Professor  of  Obstetrics  In  the  Jefferson  Medical  College,  Philadel- 
phia, ivsmo  volume  of  436  pages,  illustrated.  Buckram,  $1.75  net 

Macfarlane's  Gynecology  for  Nurses 

ILLUSTRATED 

Dr.  A.  M.  Seabrook,  Woman's  Hospital  of  Philadelphia,  says: 
"  It  is  a  most  admirable  little  book,  covering  in  a  concise  but 
attractive  way  the  subject  from  the  nurse's  standpoint.  You 
certainly  keep  up  to  date  in  all  these  matters,  and  are  to  be 
complimented  upon  your  progress  and  enterprise." 

A  Reference  Handbook  of  Gynecology  for  Nurses.  By  CATHARINE 
MACFARLANE,  M.  D.,  Gynecologist  to  the  Woman's  Hospital  of  Phil- 
adelphia. 32mo  of  150  pages,  with  70  illustrations.  Flexible  leather, 
$1.25  net. 


McKenzie's  Exercise  in  Education  and  Medicine 

Exercise  in  Education  and  Medicine.  By  R.  TAIT 
MCKENZIE,  B.A.,  M.D.,  Professor  of  Physical  Educa- 
tion, and  Director  of  the  Department,  University  of 
Pennsylvania.  Octavo  of  406  pages,  with  346  illustra- 
tions. Cloth,  $3.50  net. 


Manhattan    Hospital    Eye,    Ear,    Nose, 

and    Throat     Nursing  ILLUSTRATED 

This  is  a  practical  book,  prepared  by  surgeons  who,  from  their 
experience  in  the  operating  amphitheatre  and  at  the  bedside, 
have  realized  the  shortcomings  of  present  nursing  books  in 
regard  to  eye,  ear,  nose,  and  throat  nursing. 

Nursing  in  Diseases  of  the  Eye,  Ear,  Nose  and  Throat.  By  the 
Committee  on  Nurses  of  the  Manhattan  Eye,  Ear,  and  Throat  Hospital: 
J.  EDWARD  GILES,  M.  D.,  Surgeon  in  Eye  Department;  ARTHUR  B. 
DUEL,  M.  D.,  (chairman),  Surgeon  in  Ear  Department;  HARMON 
SMITH,  M.  D.,  Surgeon  in  Throat  Department.  Assisted  by  JOHN  R. 
SHANNON,  M.  D.,  Assistant  Surgeon  in  Eye  Department;  and  JOHN 
R.  PAGE,  M.  D.,  Assistant  Surgeon  in  Ear"  Department.  With  chap- 
ters by  HERBERT  B.  WILCOX,  M.  D.,  Attending  Physician  to  the  Hos- 
pital ;  and  Miis  EUGENIA  D.  AYERS,  Superintendent  of  Nurses.  12010 
of  260  pages,  illustrated.  Cloth,  $1.50  net. 

Friedenwald     and    Ruhrah's    Dietetics 

1  1  lirSeS 


NEW  (2d)  EDITION 

This  work  has  been  prepared  to  meet  the  needs  of  the  nurse, 
both  in  training  school  and  after  graduation.  American  Jour- 
nal of  Nursing  says  it  "is  exactly  the  book  for  which  nurses 
and  others  have  long  and  vainly  sought." 

Dietetics  for  Nurses.  By  JULIUS  FRIEDENWALD,  M.  D.,  Professor 
of  Diseases  of  the  Stomach,  and  JOHN  RUHRAH,  M.  D.,  Professor  of 
Diseases  of  Children,  College  of  Physicians  and  Surgeons,  Baltimore. 
121710  volume  of  395  pages.  Cloth,  $1.50  net 

Friedenwald  &  Ruhrah  on  Diet  THIRD  EDITION 

Diet  in  Health  and  Disease.  By  JULIUS  FRIEDEN- 
WAI,D,  M.D.,  and  JOHN  RUHRAH,  M.D.  Octavo  vol- 
ume of  764  pages.  Cloth,  $4.00  net. 

Galbraith's  Personal  Hygiene  and  Physical 
Training  for  Women  JUST  ISSUED 

Personal  Hygiene  and  Physical  Training  for  Women.  By  ANNA  M. 
GALBRAITH,  M.  D.,  Fellow  New  York  Academy  of  Medicine.  i2tno 
of  371  pages,  illustrated.  Cloth,  $2.00  net. 

Galbraith's  Four  Epochs  of  Woman's  Life 

THE  NEW  (2d)   EDITION 

The  Four  Epochs  of  Woman's  Life.  By  ANNA  M.  GALBRAITH,  M.D. 
With  an  Introductory  Note  by  JOHN  H.  MUSSER,  M.  D.,  University 
of  Pennsylvania.  iamo  of  247  pages.  Cloth,  $1.50  net. 


McCombs'  Diseases  of  Children  for  Nurses 

JUST  ISSUED— NEW  (2d)  EDITION 

Dr.  McCombs'  experience  in  lecturing  to  nurses  has  enabled 
him  to  emphasize/^?/  those  points  that  nurses  most  need  to  know. 
National  Hospital  Record  says:  "We  have  needed  a  good 
book  on  children's  diseases  and  this  volume  admirably  fills 
the  want."  The  nurse's  side  has  been  written  by  head 
nurses,  very  valuable  being  the  work  of  Miss  Jennie  Manly. 

Diseases  of  Children  for  Nurses.  By  ROBERT  S.  McCOMBS,  M.  D., 
Instructor  of  Nurses  at  the  Children's  Hospital  of  Philadelphia.  i2mo 
of  470  pages,  illustrated.  Cloth:  $2.00  net 

Wilson's  Obstetric  Nursing 

In  Dr.  Wilson's  work  the  entire  subject  is  covered  from  the 
beginning  of  pregnancy,  its  course,  signs,  labor,  its  actual 
accomplishment,  the  puerperium  and  care  of  the  infant. 
American  Journal  of  Obstetrics  says:  "  Every  page  empasizes 
the  nurse's  relation  to  the  case." 

A  Reference  Handbook  of  Obstetric  Nursing.  By  W.  REYNOLDS 
WILSON,  M.D.,  Visiting  Physician  to  the  Philadelphia  Lying-in  Char- 
ity. 3amo  of  355  pages,  illustrated.  Flexible  leather,  $1.25  net 


NEW  (6th)  EDITION 


American  Pocket  Dictionary 

The  Trained  Nurse  and  Hospital  Review  says:  "We  have 
had  many  occasions  to  refer  to  this  dictionary,  and  in  every 
instance  we  have  found  the  desired  information." 

American  Pocket  Medical  Dictionary.  Edited  by  W.  A.  NEWMAN 
DORLAND,  A.  M.,  M.  D.,  Loyola  University,  Chicago.  Flexible 
leather,  gold  edges,  $1.00  net;  with  patent  thumb  index,  $1.25  net. 


SECOND 
EDITION 


Lewis'  Anatomy  and  Physiology 

Nurses  Joarnal of  Pacific  Coast  says  "it  is  not  in  any  sense 
rudimentary,  but  comprehensive  in  its  treatment  of  the  sub- 
jects." The  low  price  makes  this  book  particularly  attractive. 

Anatomy  and  Physiology  for  Nurses.  By  LERov  LEWIS,  M.D.,  Lec- 
turer on  Anatomy  and  Physiology  for  Nurses,  Lewis  Hospital,  Bay 
City,  Mich.  i2mo  of  375  pages,  150  illustrations.  Cloth,  $1.7?  net 


Borland's  Illustrated  Dictionary 


NEW    (5th) 
EDITION 

The  American  Illustrated  Medical  Dictionary.  Edited  by  W.  A.  N. 
DORLAND,  M.D.  Large  octavo  of  876  pages,  293  illustrations,  ng  in 
colors.  Flexible  leather,  $4. 50  net;  thumb  indexed,  $5.00  net. 


Paul's  Materia  Medica 


A  Text-Book  of  Materia  Medica  for  Nurses.  By  GEORGE  P.  PAUL, M.D.,. 
Samaritan  Hospital,  Troy,  N.  Y.     i2mo  of  240  pages.     Cloth,  $1.50  net. 


Paul's  Fever  Nursing 


Nursing  in  the  Acute  Infectious  Fevers.      By  GEORGE  P.  PAUL,  M.D. 

Cloth,  $1.00  net. 


Hoxie's  Medicine  for  Nurses 


Practice  of  Medicine  for  Nurses.  By  GEORGE  HOWARD  HOXIE,  M.D., 
University  of  Kansas.  With  a  chapter  on  Technic  of  Nursing  by 
PEARL  L.  LAPTAD.  iamo  of  284  pages,  illustrated.  Cloth,  $1.50  net. 


Grafstrom's  Mechano-therapy 


Mechano-therapy  (Massage  and  Medical  Gymnastics).       By  AXEL   V. 
GRAFSTROM,   B'.Sc.    M.D.,      12010,  200  page..  Cloth,  $1.25  net] 


NEW  (7th)  EDITION 


Nancrede's  Anatomy 

Esseniials  of  Anatomy.  CHARLES  B.  G.  DENANCREDE,  M.D.,  Univers- 
ity of  Michigan.  i2mo,  400  pages,  180  illustrations.  Cloth,  $1.00  net 

Morrow's  Immediate  Care  of  Injured 

Immediate  Care  of  the  Injured.  By  ALBERT  S.  MORROW,  M.D,,  New 
York  City  Home  for  Aged  and  Infirm.  Octavo  of  340  pages,  with  238 
illustrations.  Cloth,  $2.50  net. 

Register's  Fever  Nursing 

A  Text  Book  on  Practical  Fever  Nursing.  By  EDWARD  C.  REGISTER, 
M.D.,  North  Carolina  Medical  College.  Octavo  of  350  pages,  illus- 
trated. Cloth,  $2.=;o  net. 

Pyle's  Personal  Hygiene 


NEW    (4th)    EDITION 

A  Manual  of  Personal  Hygiene.  Edited  by  WALTER  L.  PYLE,  M.D. 
Wills  Eye  Hospital,  Philadelphia.  lamo,  472  pages,  illus.  $1.50  net. 

Morris'  Materia  Medica         NEW  (7.h)  EDITION 

Essentials  of  Materia  Medica,  Therapeutics,  and  Prescription  Writing. 
By  HENRY  MORRIS,  M.D.  Revised  by  W.  A.  BASTEDO,  M.D.,  Colum- 
bia University,  N.  Y.  12010  of  300  pages,  illustrated.  Cloth,  $1.00  net. 

Griffith's  Care  of  the  Baby     NEw  SS 

The  Care  of  the  Baby.  By  J.  P.  CROZER  GRIFFITH,  M.D.,  Univers- 
ity of  Pennsylvania.  12010  of  455  pages,  illustrated.  Cloth,  $1.50  net. 


UNIVERSITY  OF  CALIFORNIA  AIKD1CAL  SCHOOL   LIBRARY 


THIS  .BOOK  IS   DUE   ON   THE   LAST   DATE 
STAMPED  BELOW 


DEC  a« 

MAY  7  -  193a 
•933 


241941 

21943 


28  DAY 

JUL  2  2  1995 


ADO  3  Q  995 


lm-11,'18 


631642 


3   1378  00631    6429 


$54 


Fiske  Annette 
Structure  and  func- 


tions   of   tfhe   body. 


DEC  26  192feN  IB  1930 


67S 


University  of  California  Medical  School  Library 


